We evaluated changes in hematology and chemical profile, and the tissue retention of hematoporphyrin derivative (HpD) following the intravenous injection in dogs. HpD at concentrations of 1, 5, 10, and 15 mg/kg was intravenously injected to 16 dogs (n=4 each) and complete blood count (CBC) and blood chemistry were performed on days 1, 3, 5, and 7 after the injection. To examine tissue retention, HpD (5 mg/kg) was administered to 15 dogs and 3 dogs were euthanized on days 1, 2, 7, 14, and 28 after the injection, respectively, to collect the skin, muscle, small intestine, spleen, kidney and liver as tissue samples. There were no significant changes in CBC and blood chemical profile except for an increase in LDH concentrations in dogs given 10 and 15 mg/kg of HpD at day 3. The levels of HpD retention in the tissues were ranked in the following order: liver > kidney > spleen > intestine > muscle > skin.