The study was conducted to determine the correlation between zinc and heavy metal concentrations (lead, cadmium, arsenic) in different ZnO sources. Seven ZnO samples submitted to Laboratory 1 were analyzed for Zn and heavy metal concentrations using atomic absorption spectrophotometry (AAS). Another ten samples submitted to Laboratory 2 were analyzed for Zn using AAS and for heavy metals using inductively coupled plasma–atomic emission spectrometry. Correlations were determined for the data gathered. Concentrations of Zn, Pb, Cd and As ranged from 3.6 to 79.2%, 0 to 1341.2 ppm, 0 to 178.3 ppm, and 0.4 to 12.9 ppm, respectively. Zinc content in different ZnO sources was not correlated with heavy metal concentrations. For Laboratory 1, Pb concentration detected in ZnO was positively correlated (P<0.001) with Cd, whereas in Laboratory 2, Pb was negatively correlated (P<0.001) with Cd. Arsenic concentration found in ZnO tended (P<0.07) to positively correlate with Pb (r=0.72) and Cd (r=0.75) for Laboratory 1. The present study shows wide variability of Zn and heavy metal concentrations in commercially available ZnO sources. It is recommended that heavy metal concentration in ZnO should be checked regardless of the Zn content.