A motor gasoline with an octane number of at least 95, and containing at least 30 per cent by volume of components boiling up to 100 DEG C., is prepared by separating a heavy fraction having an initial boiling point between 130 and 135 DEG C. from a reformate obtained by catalytic reforming in the presence of a platinum-containing catalyst and mixing this heavy reformate fraction with at least 80 per cent by volume (calculated on the heavy reformate fraction) of a light fraction, boiling up to 100-115 DEG C., of a gasoline obtained by catalytic cracking, and with a small proportion, not exceeding 20 per cent by volume (calculated on the final product), of a third component, comprising one or more hydrocarbons with an octane number of at least 90 and a boiling point of 100-130 DEG C., or a mixture of hydrocarbons with an octane number of at least 90 and a boiling range lying between 100 DEG C. and 130 DEG C. The third component may be a hydrocarbon mixture consisting of propylene and/or butylene polymers and/or of alkylate of isobutane with propylene and/or butylenes and/or pentylenes, the boiling range of which mixture is within the gasoline boiling range, and preferably predominantly between approximately 100 DEG and 130 DEG C. Alternatively, toluene or a mixture of hydrocarbons containing at least 75 per cent of toluene may be used as third component, if desired in admixture with the above-mentioned third component consisting of polymers and/or alkylate. A small proportion, e.g. 2-6 per cent, of butane may be added to the motor gasoline to bring its vapour pressure to the desired value. Anti-knock additives (e.g. tetra-ethyl lead) and anti-oxidants may also be added to the motor gasoline. The light reformate fraction, boiling below 130-135 DEG C., or a selected fraction thereof, may also be added to the motor gasoline in an amount not exceeding 35 per cent by volume, with respect to the heavy reformate fraction. Alternatively, a second motor gasoline may be prepared by mixing this light reformate fraction, or a fraction thereof, with the portion of catalytically cracked gasoline boiling above 100-115 DEG C. and with a light straight-run petroleum distillate boiling below 100 DEG C. Butane, isopentane, tetra-ethyl lead and anti-oxidants may be added to this second motor gasoline. Apparatus is described in which the three ingredients of both motor gasolines are prepared from a single crude petroleum.ALSO:A motor gasoline (see Group III) with an octane number of at least 95, and containing at least 30 per cent by volume of components boiling up to 100 DEG C., is prepared by separating a heavy fraction having an initial boiling point between 130 DEG and 135 DEG C. from a reformate obtained by catalytic reforming in the presence of a platinum-containing catalyst and mixing this heavy reformate fraction with at least 80 per cent by volume (calculated on the heavy reformate fraction) of a light fraction, boiling up to 100-115 DEG C., of a gasoline obtained by catalytic cracking and with a small proportion, not exceeding 20 per cent by volume (calculated on the final product) of a third component, comprising one or more hydrocarbons with an octane number of at least 90 and a boiling point of 100-130 DEG C., or a mixture of hydrocarbons with an octane number of at least 90 and a boiling range lying between 100 and 130 DEG C. The light reformate fraction, boiling below 130-135 DEG C., or a selected fraction thereof, may also be added to the motor gasoline in an amount not exceeding 35 per cent by volume, with respect to the heavy reformate fraction. Alternatively, a second motor gasoline may be prepared by mixing this light reformate fraction, or a fraction thereof, with the portion of the catalytically cracked gasoline boiling above 100-115 DEG C. and with a light straight-run petroleum distillate boiling below 100 DEG C. Apparatus is described in which the three ingredients of both motor gasolines are prepared from a single crude petroleum.