This study was to determine intestinal helminths and their effects on anthropometric, hematological and metabolic parameters among patients in two teaching hospitals in the region of N'Djamena (Chad). Patients consisting of 300 adults at the gastroenterology service of the National Reference Teaching Hospital (NRTH) and 112 children at the pediatric ward in Mother and Child Teaching Hospital (MCTH). Their ages ranged from 3 months to 75 years. This study was conducted from July to September, 2017. Stool samples were collected from all patients and examined using the following techniques: Kato Katz, direct method and Willis floatation. Blood samples were collected to determine haemoglobin, eosinophil and leucocytes. From a total of 412 subjects, 87 (21.11%) had gastrointestinal helminth infections. Ten parasitic species were found: Hymenolepis nana, Ascaris lumbricoides, Teania saginata Trichuris trichura, Ankylostoma duodenale, Schistosoma mansoni, Hymenolepis diminuta , Enterobius vermicularis, Strongyloides stercoralis, and Teania solium. Hymenolepis nana and Ascaris lumbricoides were isolated from almost all the age groups. Parasitic infections were higher in children (49.10%) while in adults 10.67%. Patients infected by helminth species presented a lower average of haemoglobin level (8.62±1.043). The most frequent symptoms found were diarrhoea (5.33%) and abdominal pain (5.58%).