Bivalvia is a class in the phylum Mollusca, including blood cockle shell (Anadara granosa) and scallop shell (Placuna placenta). Both species have become food commodities that are consumed leaving their shells as unused waste. Based on this, research that examines other benefits of shell waste is urgently needed so that shell waste can be optimally explored. In this study, the samples were obtained from the Banyuasin water, ​​South Sumatra in July 2021. The samples were classified into three size categories: A. granosa A (> 40 g), B (20-30 g) and C (< 20 g), while P. placenta was differentiated into A (> 13 g), B (9-12 g) and C (< 9 g). For the quantitative analysis of the calcium, atomic absorption spectroscopy was used; whereas for phosphorus, UV-Vis spectrophotometry was utilized. The ANOVA, the least significant difference test and the independent sample T-Test were analyzed for statistical analysis. Based on the results, the calcium content in the  P. placenta was 41.13%, 38.75%, 35.81%, and phosphorus was 0.00054%, 0.00043%, 0.00014%. The  A. granosa contained calcium with percentages of 45.74, 42.17 and 37.11, while phosphorus recorded values of 0.00049%, 0.00035% and 0.00001%. The ANOVA showed significant differences between sample categories in terms of calcium and phosphorus content (P<0.05). LSD results showed that each category differed significantly. The independent sample T-Test for the calcium of A. granosa and P. placenta with a Sig-2 tailed value of 0.007 resulted in a significant average difference, while the phosphorus content with a Sig-2 tailed value of 0.544 indicated no significant average difference. Based on this study, both types of shell minerals should be used as an alternative source of calcium and phosphorus.