Statement of problem: Zinc phosphate and polycarboxilate cement have wide application in operative, pedodontics dentistry and fixed prosthodontics. The Ariadent zinc phosphate and polycarboxilate cements are manufactured in Iran. One of the important and necessary properties of each cement to be used in oral cavity is its low solubility.Purpose: The purpose of the present study was to determine and compare the solubility of Harvared zinc phosphate and polycarboxilate cement with Ariadent.Materials and Methods: In this experimental study that was based on specification No 2725 and 2726 of Iranian standard, ten discs shaped samples with 1±0.03 mm width and 10±0.3 mm diameter was constructed for each cement. Zinc phosphate solubility with spectrophotometry and polycarboxilate solubility with conductivity evaluation was measured. The data were analyzed with T test. Statistical analysis was significant ( p <0.05).Results: The mean value of solubility for Harvard and Ariadent zinc phosphate cement was in order 1.23±0.24 and 0.86±0.15 mgr P205 per gr. There was statistically significant difference between the two above cements ( p =0.001). The mean value of solubility for Harvard and Ariadent polycarboxilate cement was in order 39.27±4.40 and 37.85±3.05 simence on the meter per kg. There was no statistically significant difference between the two above cements ( p =0.4).Conclusion: In accordance to determined values from Iranian standard No 2725 and 2726, the mean value of solubility of 4 experimental cements in this study was within standard limits.Key words: Zinc phosphate cement, polycarboxilate cement, solubility.