The invention comprises fat-soluble azo-dyestuffs which are free from sulphonic acid groups and contain at least one hydroxyl group bound to the residue of the coupling component and at least one carboxylic acid ester group having an aliphatic or cycloaliphatic alcohol residue of 8-18 carbon atoms and, between the ester group and an azo linkage, at least one aromatic 6-membered ring. They may be made by condensing appropriate acid halides and aliphatic or cycloaliphatic alcohols using conventional methods, advantageously with an excess of alcohol as solvent and at about 100-150 DEG C. The acid halides are also made by conventional methods from the free acids. Carboxylic acids specified are 2-methoxy-5-chloro - aniline --> 2 - naphthol - 3 - or - 6 - carboxylic acid, 2 - carbethoxy - aniline --> 1 - (41 - carboxyphenyl) - 3 - methyl - 5 - pyrazolone, 2 - nitro - 4 - methyl - aniline --> acetoacetylaminobenzene - 41 - carboxylic acid, 3 - carboxy - and 4 - methylcarboxy - aniline --> b - naphthol, 2 - nitro - 4 - carboxy - aniline --> 2 - naphthol - 3 - carboxylic acid. Amines specified for diazotization in the preparation of the carboxylic acids are 2-, 3- and 4-chloro-, 2-methyl- or -methoxy-5-nitro-, 2-methyl-3-, -4-, -5- and -6-chloro-, 2-nitro-4-chloro-methyl- or -methoxy-, 2-methoxy-5-methyl- and 2,5-dimethyl- and -dimethoxy-4-chloro - anilines, 2 - amino - 4,41 - dichloro-diphenyl ether, 2-amino - diphenyl sulphone, 1 - amino - 2,5 - dimethoxy - or - diethoxy - 4 - benzoylamino - benzene, 1 - amino - 2 - methoxy - 4 - benzoylamino - 5 - methylbenzene, amino-chrysene and -pyrene, 4-amino-2-methyl-5 - methoxy - 1 - benzoylaminobenzene, 4 - amino - 21,31 - dimethyl - 1,11 - azobenzene, 4-amino - 2,5 - dimethoxy - 41 - nitro - 21,61 - di-chloro - 1,11 - azobenzene, aminodiphenylamines and N-substitution products thereof, 4-chloro-2-, 2-chloro- or ethyl-sulphone-5-, and 3,5 - di - trifluoromethylanilines, 2 - methoxy-5-ethyl- or -benzyl-sulphone aniline, and 2-methoxyaniline - 5 - sulphodiethylamide. Indicated as diazo components containing carboxy groups are aminobenzoic acids and halogen, alkoxy and nitro derivatives and alkylsulphones thereof. It is also stated that naphthalenic compounds may be used as diazo components. Specified coupling components are 2-naphthol-3-carboxylic acid and its methyl ester, 2-oxycarbazole-3-carboxylic acid and its N-alkyl-derivatives, 2 - oxyanthracene - 3 - carboxylic acid, 3 - oxy - diphenylene - oxide or - sulphide-2-carboxylic acid, 1-phenyl-3-methyl-5-pyrazolone - 41 - carboxylic acid, 1 - acetoacetylaminobenzene-2-, -3- and -4-carboxylic acids, 1 - benzoylacetylaminobenzene - 3 - and - 4 - carboxylic acids, 4-methyl-2-carboxyphenol and a - or b -resorcylic acid. Branch or straight chain alcohols may be used. The alcohols may be unsaturated or saturated. Dihydric alcohols may be used and such alcohols may be combined with the acid halides in the mol. ratio of 1 to 2. The dyestuffs are used in the dyeing of fats and waxes or materials made therefrom. Examples and Tables are provided illustrating the preparation of the dyestuffs and their use in colouring processes coupling components used additional to those specified above being a - and b -naphthols, 6 - bromo - 1 - acetylamino -, - methoxy- and -methyl- and 8-acetyl-, -butyryl- and -carbethoxy-amino-2-naphthols, 5,8-dichloro-1-naphthol, 2 - naphthol - 6 - oxyacetic acid, 2 - naphthol - 3 - carboxylic acid anilide - 31-carboxylic acid, -3-carboxylic acid, -21-methyl-, -chloro-, -ethoxy- and methoxy- and 41-methyl-phenylamides and -3-carboxylic acid morpholide and phenyl- and -cyclohexyl-amides, 1 - naphthol - (4) - acetyl and phenylketones, 1 - acetoacetylamino - 2 - chloro - and - 2-methoxy - 4 - chloro - 5 - methyl - benzenes, 4 - acetoacetylamino - benzoic and - phenylacetic acids, 4 - chloro - 2 - acetoacetylaminophenoxyacetic acid, 3-acetoacetylamino-4-methoxy-phenylacetic acid, 4-acetoacetyl-aminobenzoic acid, 1-(21-chlorophenyl) - or - phenyl - 3 - methyl - 5 - pyrazolones and resorcinol, additional diazo components being 4-chloro- or -methoxy-3- and -3-nitro-4-aminobenzoic acids, o-, m- and p-aminobenzoic acids, 1-methyl-2- and 4-methoxy-3-aminophenyl acetic acids, 4-methyl- or -chloro-2- and 4-methoxy-3-aminophenoxyacetic acids, 41-chloro-2-aminodiphenyl-ether-3-carboxylic acid, 2,4-dichloro-, 2-methyl-4 - methoxy -, 4 - nitro - 2 - methoxy -, 2 - chloro - 5 - methyl - 4 - cyano - and 4 - methylanilines, 2-aminobenzoic acid methyl and ethyl esters, 2-amino-5-chloro-benzoic acid diethylamide, 41-aminophenyl- and 4-chloro-2-amino - 1,11 - azobenzenes, 4 - amino - 2,5-dimethoxy- and 5-methoxy-4-amino-2-methyl-1,11 - azobenzene - 31 - carboxylic acids, 4 - amino - 5 - methoxy - 2 - methyl - phenylazo-21 - chlorobenzene - 51 - carboxylic acid, nonyl esters of 2-, 3- and 4-amino-, 4-methoxy- and -chloro-3-amino-benzoic acids and 3-amino-4-methoxy-phenylacetic acid, 2-aminobenzoic acid dodecyl ester and 4-methoxy-3-amino-benzoic acid octyl ester, the alcohols used being isooctanol, 2-ethyl hexanol, n-nonanol, n-dodecanol, stearyl, cetyl-stearyl, cetyl and oleyl. Apart from the methods outlined above the examples also illustrate the direct preparation of the dyestuffs by usual coupling processes from diazo components which contain the required ester grouping. Specification 739,701, [Group IV (a)], is referred to.ALSO:Fat-soluble azo dyestuffs which are free from sulphonic acid groups and have at least one hydroxyl group bound to the residue of the coupling component and at least one carboxylic acid ester group having an aliphatic or cycloaliphatic alcohol residue of 8-18 carbon atoms and also contain between the ester group and an azo linkage at least one aromatic 6-membered ring are used as colouring materials for wood stains, floor and furniture polish, candles and other waxy articles. For the specified dyestuffs and their preparation (see Group IV (c)). Specification 739,701, [Group IV (a)], is referred to.ALSO:Fat-soluble azo-dyestuffs which are free from sulphonic acid groups and have at least one hydroxyl group bound to the residue of the coupling compartment and at least one carboxylic acid ester group having an aliphatic or cycloaliphatic alcohol residue of 8-18 carbon atoms and also contain between the ester groups and an azo linkage at least one aromatic 6-membered ring are used for colouring compositions containing synthetic resins. In examples the preparation of printing pastes from (11) 4-aminobenzoic acid nonyl ester --> 8-carbethoxyamino-2-naphthol admixed with a modified melamine resin, toluene and benzene; (14) 2-aminobenzoic acid nonyl ester --> 1-(21-chloro) - phenyl - 3 - methyl - 5 - pyrazolone; and (16) 4-chloro-3-aminobenzoic acid nonyl ester --> 2-naphthol-3-carboxylic acid 21-methoxyphenylamide admixed with polyethylene in tetrahydronaphthalene solution and condensation products from di-(4-oxyphenyl)-dimethyl methane and ethylene glycol with epichlorhydrin, toluene and triethylene tetramine; and (15) 3-aminobenzoic acid nonyl ester --> 2-naphthol-6-oxyacetic acid admixed with polyethylene in tetrahydronaphthalene solution and a condensation product of di-(4-oxyphenyl)-dimethyl urethane with epichlorhydrin, toluene and triethylene tetramine are described and in (12) a lacquer is prepared from 4-nitro-2-methoxy - aniline --> 2 - naphthol - 3 - carboxylic acid nonyl ester, nitrocellulose, a melamine resin, an alkyd resin, dibutyl phthalate, butyl acetate and toluene. Specification 739,701 is referred to.