Peripheral giant cell granuloma (P.G.C.G) is an exophytic lesion with an approximate size of 0.5-1.5 mm. It usually occurs on gingival and alveolar ridge of mandible particularly in molar and premolar region. The relation of serum calcium (Ca), Phosphor (P), and alkaline phosphatase (Alk) levels to P.G.C.G is yet controversial. In this descriptive study, 33 patients with P.G.C.G were chosen and serum Ca, P, and Alk levels compared with the normal range. In all patients the level of Ca was in the normal range. Phosphor (P) was in the normal range in all patients over 17 years old and 80% under 17 years. The level of ALK in 75.8 percent of the patients over 17 years and 90% under 17 years was in the normal range. In conclusion, no relationship was found between serum changes and P.G.C.G. It means P.G.C.G can be compeletly independent lesions from serum changes.