Tanzania Journal of Agricultural Sciences 2002, Vo1(1) : 29-38Genetic diversity among seven Tanzanian goat populations (Ujiji, Sukuma, Ugogo, Maasai, Mbeya, Newala and Coastal goats) was investigated by determining polymorphisms at 19 microsatellite DNA loci, West African Dwarf Tswana, Landim and Toggenburg were included to serve as reference breeds. Among the Tanzanian populations, mean number of alleles per locus was highest (6.26 ± 0.670) in Sukuma and lowest (5.74 ± 0.545) in Newala. Gene diversity ranged from 0.553 ± 0.036 (Newala goats) to 0.646 ± 0.028 (Mbeya goats). The coefficient of gene differentiation (Gsr) indicated that 13% of the genetic diversity in all populations was due to difference between the populations. The genetic distance values ranged from 0. 068 (between Sukuma and Ugogo goats) to 0.2178 (between Ujiji and Coastal goats). The neighbour-joining dendrogram constructed to show population relationships indicated that the Tanzanian populations were separated from the populations, used as reference, breeds. The dendrogram revealed three, sub-clusters of the Tanzanian populations. Coastal and Maasai goats Ugogo and Ujiji goats and Sukuma Mbeya and Newala goats. The principal component analysis separated the Newala goats from the other Tanzanian goat populations. It is concluded that the level of genetic variation within, the goat populatiions was reasonably high and there was no significant difference between the population with respect to the number of alleles and the level of heterozygosity.