Majority of clinical decisions are said to be based on laboratory test results. Therefore, discrepant and unreliable laboratory results may cause serious consequences for the health of individuals and the society. This study is designed to evaluate the degree of accuracy and precision of laboratory test results from different laboratories. Fifty blood samples were collected from apparently healthy subjects and sent to 3 different participating hospital laboratories designated as A, B and C within northern Nigeria over a ten-week period. The laboratories, all using standard hematology techniques, undertook Hb estimation, total WBC counts and PCV measurements in an inter-laboratory quality control assessment. The study revealed that laboratories B and C obtained significantly lower mean values of 13.20 g/dl and 13.80 g/dl for hemoglobin respectively compared to 14.60 g/dl from the originating laboratory (p<0.01). Meanwhile, the mean WBC values for laboratories B and C appeared significantly higher than the accurate mean. Two laboratories (B and C) also obtained mean values of PCV slightly different from the accurate one while laboratory A had similar mean PCV value to the accurate one. Generally, higher variance ratios between laboratories than between samples (P<0.01) was observed in hemoglobin estimation and WBC count, while PCV showed a high variance ratio between samples than laboratories. However, the reproducibility of test results of participating laboratories was good. With the increasing reliance on laboratory test results for the diagnosis of diseases, clinical laboratories must embark on regular intra- and inter-laboratory quality evaluations to minimize misdiagnosis.