Melamine contamination is known as a significant health risk and seriously considered by scientists worldwide. Cyanuric acid is one of the melamine by-products that contribute to its renal toxicity via the formation of melamine cyanurate crystals in the kidney. Therefore, co-determination of melamine and cyanuric acid in both powder and liquid milk samples has grown significantly throughout the world. High-performance LC with ultraviolet detection has been used as a simple and rapid method for the determination of melamine and cyanuric acid in powder and liquid milk samples and the results confirmed by using LC-MS/MS. In this study, nine powder milk and five liquid milk samples from different brands available in Iranian markets were chosen randomly and analysed. SPE column was used to clean up the samples. The results showed that except one brand of milk powder and liquid milk, all other samples were contaminated with melamine in the range of 1.50-30.32 μg/g for milk powder and 0.11-1.48 μg/mL for liquid milk. No cyanuric acid was detected in milk powder or liquid milk samples, which reduces the risk of melamine toxicity for consumers.