The effects of ten days consumption of vegetarian diet on total peptide YY (PYY) and appetite perceptions were investigated in fifteen males. The experiment was a randomized cross-over design with two main trials including normal and vegetarian diets. Total PYY, glucose, and lipid profiles were assessed on day one and day eleven. Additionally, appetite perceptions were measured. The data were analyzed using two way repeated measures ANOVA and paired t-tests. There were no changes in fasting total PYY, glucose, high density lipoprotein, or subjective feelings of fullness following consumption of a vegetarian diet. However, cholesterol, and low density lipoprotein decreased significantly while the areas under the curve of subjective feelings of hunger in the vegetarian diet was higher than in the control trials. It is concluded that the consumption of a vegetarian diet induces increased subjective feelings of hunger but with no impact on total PYY or subjective feelings of fullness.