Intake of unsafe food causes many acute and life-long diseases, ranging from diarrheal diseases to various forms of cancer. Thus, it is imperative that safety issues on food adulteration and heavy metals contamination be evaluated for the benefits of the consuming public. Consequently, oxidation stability and heavy metal analyses on used cooking oil and four selected street-vended foods from three different sampling sites were done. Analyses of test parameters were performed using standard methods and procedures. Overall results of the analyses with three trials each showed that peroxide value, free fatty acids, cadmium (Cd) and lead (Pb) did not conform to the allowable levels set for the food products. The peroxide value was three to eight times higher than the limit of 10meq/kg since it ranges from 33.33 - 86.67meq/kg whereas Cd and Pb showed concentration of 0.60 – 1.57 ppm and 30.00-35.00 ppm, respectively. On the other hand, percent free fatty acids (%FFA) ranges from 0.72 to 0.93% on used cooking oil while selected street-vended foods FFA status were recorded at the range of 1.49 to 2.92%. The results clearly indicate oxidative rancidity due to repetitive use of cooking oil and heavy metal contamination on the test samples which were found to be significantly higher than the maximum limits. This could mean that prolonged exposure to these street vended foods is detrimental to human health. The high level of POV, Cd and Pb of these products can significantly pose food poisoning, foodborne disease, neurotoxicity and even cancer.