Abstract A database of 349 treatment mean observations, representing 3404 goats from 73 publications between 1973 and 2003, was used to determine metabolizable protein (MP) requirements for maintenance (MP m ) and growth (MP g ) of goats. Published CP degradation properties of feedstuffs and proportions of dietary ingredients were used to estimate MP intake (MPI, g/day), which was regressed against ADG, with both variables scaled by BW 0.75 . Goats were classified as meat (≥50% Boer; 60 observations), dairy (selected for milk production; 129 observations) and indigenous (160 observations) biotypes. Because of differences ( P MPI =2.55( S.E. =0.360)+(0.441( S.E. =0.0276)× ADG ) (n=58;R 2 =0.82) ; dairy: MPI =2.83( S.E. =0.344)+(0.299( S.E. =0.0238)× ADG ) (n=123;R 2 =0.57) ; and indigenous: MPI =3.23( S.E. =0.212)+(0.281( S.E. =0.0304)× ADG ) (n=152;R 2 =0.36) . Intercepts did not differ among biotypes ( P =0.37), but the slope for meat goats differed ( P n =150) and evaluation ( n =125) subsets. Using the equation derived from the development data subset for dairy and indigenous goats (i.e., MPI =3.14( S.E. =0.189)+(0.285( S.E. =0.0168)× ADG ) (n=144;R 2 =0.67) ), MPI for the evaluation subset was predicted; regressing observed against predicted MPI of the evaluation data subset resulted in an intercept and slope not different from 0 and 1, respectively ( P >0.05). The equation from the development subset for dairy and indigenous goats was compared with the equation from the meat goat data set; there was a difference ( P P =0.25). Therefore, a dummy variable ( D =1 for meat goats and 0 otherwise) was used to develop a common intercept equation: MPI =3.07( S.E. =0.165)+(0.290( S.E. =0.0150)× ADG )+(0.114( S.E. =0.0162)×D× ADG ) (n=202;R 2 =0.75) . In conclusion, based on regression of MPI against ADG, MP m was 3.07 g/kg BW 0.75 for all biotypes of growing goats, and MP g was 0.404 and 0.290 g/g ADG for meat and other (dairy and indigenous) goats, respectively.