Three phenotypic color pattern genes of the guppy (Poecilia reticulata), i.e., black caudalpeduncle (Bcp), red tail (Rdt) and variegated tail patterning (Var), were genetically analyzed and mapped. Crosses between the Tuxedo (TUX) and Green Variegated (GV) guppy strains commercially cultured in Singapore were used to determine the gene control of these color patterns. F₁ progenies were produced by single-pair reciprocal crossing between TUX and GV, while the F₂ generation was obtained from full-sib mating between F₁ males and females. F₁ and F₂ data were segregated according to color phenotypes and sex, and tested by chi-square analyses. The Bcp, Rdt and Var color pattern genes, located at different loci on the X- and Y-chromosomes, showed single gene inheritance and dominant expression in both sexes. Their corresponding recessive alleles, Bcp , Rdt and Var , do not produce any color patterns. Genotypes of Tuxedo males are proposed to be X_Bcp,Rdt,Var Y_Bcp,Rdt,Var (type I), X_{Bcp ,Rdt,Var} Y_Bcp,Rdt,Var (type II) and X_Bcp,Rdt,Var Y_{Bcp ,Rdt,Var} (type III) while females are X_Bcp,Rdt,Var X_Bcp,Rdt,Var . Green Variegated males and females have the X_{Bcp ,Rdt ,Var}Y_{Bcp ,Rdt ,Var} and X_{Bcp ,Rdt ,Var}X_{Bcp ,Rdt ,Var} genotypes, respectively. Close linkages of 3.1, 2.3 and 2.2 map units were estimated for the sex-determining region (SdR)–Rdt, Rdt–Bcp, and SdR–Var gene pairs, respectively, while Bcp was approximately 5.1 map units from the SdR. The phenotypic map order of the guppy Y-chromosome is inferred to be Var–SdR–Rdt–Bcp.