Although the river buffalo is one of the most important domestic bovids (more than 130 million animals raised in all the world), few loci have been mapped in this species by both ISH and somatic hybrid cell techniques (reviewed in Iannuzzi 1998). The five twoarmed river buffalo chromosome (BBU) pairs are the result of five centric fusion events that involved 10 homologous cattle chromosomes (CSKBB 1994). In particular, BBU2 was originated by rob (2;23), and the acrocentric BBU12 is homologous to BTA11. Only two loci have been FISH-mapped to these two chromosomes: VIL1 (bovine U17/BTA2) to BBU2q33 (Iannuzzi 1998), and GGTA1 (bovine U16/BTA11) to BBU12q36 (Iannuzzi 1998). In the present study, four type I loci (PRO C, COL3A1, ALPI, and IL1B) mapping to HSA2q (Fisher et al. 1997; Smith et al. 1997; Sonstegard et al. 1997), and previously FISH-mapped to both cattle and sheep (Sonstegard et al. 1997; Lopez-Corrales et al. 1998) were FISH-mapped to BBU2q and BBU12, extending the physical map for these two chromosomes. Our data are also discussed in light of HSA1 and HSA2 painting probe results.