Mucuna sloanei is a legume used as a soup thickener by communities in some parts of Africa countries. The effect of aqueous seed extract of M. sloanei on the haematological profile of normal albino rats was investigated for 28 days using standard methods. The results show no overall dose dependent significant difference (p > 0.05) in the serum levels of the white blood cell count, red blood cell count and its indices (haemoglobin content, pack cell volume, mean corpuscular volume, mean corpuscular haemoglobin and mean corpuscular haemoglobin concentration) of the rats throughout the duration of the experiment when compared with the control. However, a dose independent significant reduction (p < 0.05) in the white blood cell level was observed in week 3, while the decrease observed in the remaining week was not significant. The effects of the interaction between the doses and duration of treatment were not statistically significant (p > 0.05) in all the haematological parameters tested. These findings suggest that consumption of the crude seed extracts of M. sloanei may not constitute any adverse effect on the haematological indices of the consumers. However, the significant reduction in white blood cell levels observed in week 3 could compromise the body’s immunity and may predispose consumers to opportunistic and supra-infections in the long run.Keywords: Mucuna sloanei seed, aqueous extract, haematological parameters, albino rats