Heavy metals and antiretroviral drugs are both types of xenobiotics that induce disturbances in the body. This study aims to assess the hematological and body weight changes connected to simultaneous exposure to lead and Efavirenz. Twenty-eight rats equally divided into four groups were force-fed once daily with distilled water (G_(Ctrl)), lead acetate at 10 mg/kg (G_(Pb)), Efavirenz at 20 mg/kg (G_(Efv)) and lead acetate+Efavirenz (G_(Pb+Efv)). On Day 0, Day 14 and Day 28, the rats were weighted and retro-orbital blood collection was carried out for haemogram analysis. Results showed a significant decrease in hemoglobin level, haematocrit, erythrocytes and thrombocytes in G_(Pb) and G_(Pb+Efv). This anaemia has tended to be normocytic hypochromic. There was no significant difference in the rates of decrease between G_(Pb) and G_(Pb+Efv). No significant change was observed in the erythrocyte parameters in G_(Efv) and G_(Ctrl). The mean body weight of rats was significantly increased in G_(Ctrl) already from Day 7 while in G_(Efv), it is at from 21 day that, the weighty growth reached a significant level. There was no significant increase in body weight growth in G_(Pb) and G_(Pb+Efv). In conclusion, contrary to lead, Efavirenz has not induced anaemia but it has slowed the body growth with a less intensity than lead. The co-administration of lead and Efavirenz did not induced significant additive effects comparatively to lead administration alone. Further studies are necessary for verifying whether co-exposure to these two xenobiotics for a longer period would not be likely to induce a significantly higher toxicity.