Using a classification system with 4 independent entries (pigment pattern, eumelanic type, pigment alteration and white pattern), 74 adult [female][female] of F< sub>1 crossbreds of Swiss Brown with Red Pied Friuli, Limousin, Charolais and Chianina were analysed. Previously postulated genetic formulae for the A (Agouti), B (Brown), C (Albinism), D (Dilution), S (Irregular Spotting) and Bl (Blaze) loci explained the observed segregations, assuming incomplete penetrance and variable expressivity of the various heterozygous genotypes with the Ai(inverted mule stripe), Ay(phaeomelanic with eumelanic extremities) and Ar(phaeomelanic) alleles at the Agouti locus. It also appeared that the Bbs(Brown Swiss) variant for light brown is dominant over the standard allele (wild, B+) giving black eumelanin. The chinchilla mutant (Cch) was dominant over the standard allele C+(wild) at the C locus. In order to explain differences between the segregations of the Swiss Brown X Charolais and Swiss Brown X Red Pied Friuli, an allele for dilution in Charolais, different from the Dfdilution allele of the Simmental, is proposed. Its location has not yet been determined.