The African soft-furred rat (Mastomys natalensis) has been shown to be a possible model for propagation of Trypanosoma brucei gambiense. This study aimed at determining the baseline biological reference values and reproductive data of a laboratory bred Mastomys colony, which was established at TRC. In addition, the effect of cyclophosphamide (an immunosuppressant) treatment (s) on the haematological profile was investigated. The mean gestation period was 23 days and the mean litter size was eight. At birth, the pups weighed 2.4±0.23 g and the weights increased to 78.0±10.6 g in males and 53.9±4.5 g in females by 90 days. The mean haematological values were significantly (p<0.05) higher in adults than juveniles. However, there was no statistical difference of haematological values between the sexes. Cyclophosphamide treatment caused a macrocytic hypochromic anaemia, which was noted 24 hours after treatment and was more severe in animals treated more than once. Thus, in studies involving a disease that causes anaemia, repeated cyclophosphamide treatment should be limited. Our study is a contribution to the clinical and biological characterization of the disease pattern in this preferred rodent model of T. b. gambiense.