The objective of this study was to evaluate and compare serum calcium and phosphate status in pre-menopausal and postmenopausal women and determine the effect of parity in postmenopausal women. The study was a cross sectional study was carried out in a catholic mission hospital in Benin City, Nigeria. A total of 40 pre-menopausal and 280 post postmenopausal women with 40 each with parity ranging from 0 to 6 were included in this study. Following standard ethical process and laboratory procedures blood sample was obtained from each woman for estimation of serum calcium and phosphate concentrations. Statistical analysis was done using SPSS version 20 and the student t test and ANOVA carried out for statistical different at 95% confidence interval. The result showed that serum calcium (11.07 ± 1.53 mg/dl vs. 8.20 ± 0.41 mg/dl; 25.93% deficient) was significantly reduced while serum phosphate (2.39 ± 0.45 mg/dl vs. 3.71 ± 0.71 mg/dl; 55.23% surfeit) was significantly increased in postmenopausal women compared to the premenopausal women values. Compared to nulliparous postmenopausal women (8.11 ± 0.39 mg/dl), postmenopausal women in their 1st (8.49 ± 0.39 mg/dl) and 2nd (8.64 ± 0.31 mg/dl) parities have significantly higher mean serum calcium level while those in their 3rd through 6th parity have nonsignificantly lower mean serum calcium level. On the other hand, compared to the nulliparous postmenopausal women (2.66 ± 0.09 mg/dl), mean serum phosphate levels were significantly higher in irrespective of the number of parities.