No doubt, both visceral leishmaniasis and malignant malaria are more or less common in many Eastern Mediterranean Countries. Both of these arthropod-borne infectious diseases have overlapping clinical presentations. This study aimed to clarify the main clinical features and laboratory diagnostic tests. A total of forty Plasmodium falciparum patients and thirty visceral leishmaniasis patients were studied. Sheets were filled on each subject included, full history taking, full clinical examination, CBC, liver and renal function tests, x-ray chest and abdominal ultrasound, bone marrow aspiration.. The results showed that jaundice and liver affection tests were more common in malaria (jaundice, 55%, high ALT & AST, 60%) than in visceral leishmaniasis (high bilirubin, 30% high ALT & AST, 40%). Besides, the malaria affected the central nervous system (coma and impaired sensorium, 30%) more than visceral leishmaniasis (coma and impaired sensorium, 5%). The effect of visceral leishmaniasis on the lymphatic system (splenomegaly, 95% & hepatomegaly, 70%) was more than malaria (70% & 60% respectively). The visceral leishmaniasis markedly affected the bone marrow (anemia, 95%, thrombocytopenia, 65% & leucopenia, 70%) more than malaria (anemia, 28%, thrombocytopenia, 50% & leucopenia, 34%). Diarrhea and cough were common in visceral leishmaniasis (80% & 55% respectively) than in malaria (20% & 5%
respectively) but DIC was common in malignant malaria (20%).