Over the years medicinal plants have been using in treatment of diabetes in traditional medicine, although little scientific studies have been reported in scientific communities. The aim of this study was to evaluate the effect of hydroalcoholic extract in Melissa officinalis plant on fat profiles and the level of glucose in streptozotocin(STZ)- induced diabetic rats. In the current study, 35 Wistar rats were divided into 5 groups of seven as control group with normal diet, fatty-based diet group and the experimental groups of hypercholesterolaemic animals with minimum dose of 100, average dose of 200 and maximum dose of 300 milligrams per kilogram of Melissa officinalis extract respectively as gavage feeding. After 14 days of treatment the lipid profiles, HDL, LDL, TGand cholesterol were measured and the obtained results were analyzed using SPSS. The level of cholesterol did not change significantly in the groups treated with herbal extracts. However, the level of HDL increased and TG decreased. According to the obtained results, increase in HDL and decrease in TG levels have positive effects on diabetic rats and therefore decrease the level of blood glucose.