Several studies investigating the beneficial effects of curcumin administration in aging on the other hand, curcumin may have the potential to contribute to the development of anemia. So this study was designed to compare the hematological effects of curcumin administration in adult and aged rats. Materials and methods: Twelve adult rats 6 months old and twelve aged rats 20 months old were used in this study. Adult and aged rats were randomly and equally divided into four groups: control adult, curcumin-treated adult, control aged and curcumin-treated aged groups. Curcumin was administered in curcumin groups (50mg/Kg i.p. for 21 consecutive days). The rat tail bleeding time was assayed. Blood indices, platelets indices, in vitro platelets aggregation, total and differential white blood cells counts were measured. Results: Curcumin caused a significant decrease in red blood cells count and hemoglobin concentrations in aged group. Also curcumin significantly decreased hematocrit in adult and aged rats. In aged group curcumin significantly increased the platelets count and platelet indices. In adult group, it caused a significant increase in platelet indices only. Tail bleeding time and platelets aggregation significantly increased in curcumin-treated aged group versus control adult group. Conclusion: Curcumin administration in aged rats caused anemia, the cause of anemia may be the iron deficiency. Curcumin also caused an increase in platelets count and this may represents reactive thrombocytosis to the iron deficiency anemia and it prolonged the bleeding time. So these hematological sequelae of curcumin administration must be seriously taken in consideration with practical implications of curcumin in aging. Further researches are required to address the mechanisms of these effects.