This study focused on pesticide residue analysis of isolated ascorbic acid from overripe mango (Mangifera indica), to evaluate the amount of Vitamin C and assess the significant difference in the Vitamin C content of formulated syrup and commercial product. Overripe mangoes were collected from Bankerohan public market, Davao City. These were subjected to extraction and isolation. Resulting isolate was utilized for formulation of Vitamin C syrup and granular powder. Lastly, assay via 0.1 N iodine solution was used to evaluate percent (%) Vitamin C present in the isolate, formulated syrup and granular powder. Pesticide residue analysis was performed at National Pesticide Analytical Laboratory of the Bureau of Plant Industry, Davao City. The isolate has an amount of 23 to 24 milligrams Vitamin C per milliliter. Analysis revealed no pesticide residues present per sample of Vitamin C via GLC method. Assay of formulated syrup were 99.47% and granular powder were 100.21% content Vitamin C, passing USP limit of 99.5 to 100.5%. Comparison of Vitamin C content between commercial and formulated vitamin C syrup showed a significant difference of 2.439 as subjected to t-test analysis. This affirms that the utilization of overripe mangoes as safe Vitamin C product preparations. Furthermore, quantitative analysis shows compliance with USP standard and assures possibility of preparing quality product from trash material.