This study investigated the effect of methanol extract of Musca domestica (400mg/kg body weight) on some biomarker enzymes and haematological parameters in Trypanosoma brucei brucei -infected rats. Twenty albino rats were intraperitoneally infected with Trypanosoma brucei brucei and were grouped into five (5) groups of four (4) rats each. Group1 was set up as infected not treated (0.2ml normal saline/kg body weight), group 2 was treated with diaminazene aceturate (standard drug), group 3 as prophylactic treated (treatment for 72 hours before inoculation of parasite), group 4 as early treatment with the extract (treatment commenced after the sight of parasite) and group 5 as the control (uninfected untreated) group. Results shows significant (p<0.05) decrease in liver AST and ALT activities with concomitant increase in serum activities of the infected untreated rats when compared with the early treated, prophylactic treated, standard treated and normal control. Serum ALP activity of the infected not treated group was significantly (p<0.05) higher when compared to the control group and other experimental groups. No significant (p>0.05) difference in the liver ALP activities of the extract treated infected groups with standard drug treated group However, serum and liver GGT activities of the uninfected untreated (control) was significantly lower (p<0.05) than all the other experimental groups. Haematological studies shows significant decrease (p<0.05) in packed cell volume (PCV) , haemoglobin concentration (Hb) and red blood cell count (RBC) of infected not treated when compared to infected prophylactic treated and infected early treated. There was likewise significant increase in white blood cell count (WBC) of infected not treated compared to infected prophylactic treated and infected early treated. Findings from this study showed that methanol extract of Musca domestica larva has trypanocidal properties thereby ameliorating the T. brucei induced biochemical changes in rats.