Objective: Anaemia is commonly reported to occur in hookworm infection. Hence a detailed study was done to know about the severity of anaemia and its relation with number of hookworms in duodenum in patients with hookworm infection found while doing upper gastro intestinal endoscopy. Methods: A study of 1307 patients who had undergone upper gastro-intestinal endoscopy for a period of 5yearsand one month from May 2009 to May 2014 was carried out. In each of these 1307 patients, the first and second part of duodenum were carefully examined to find out the presence of single or multiple hookworms. In all the patients found to have hookworms in duodenum, investigations were done to know about the presence or absence of anaemia and to know about the severity of anaemia and its relation with number of hookworms in duodenum in patients with hookworm infection found while doing upper gastro intestinal endoscopy. Results: Out of these 1307 patients, 14 patients found to have hookworms in duodenum were taken into consideration for our study. Out of these14 patients with hook worms in duodenum, 5 patients did not have anaemia, 6patientshad mild anaemia, 1patient had moderate anaemia and 2 patients were found to have severe anaemia. 8outof 11patientswithabsence of anaemia and mild anaemia (73%)had only single hookworm in duodenum. But all the 3patientswithmoderate anaemia and severe anaemia had multiple hookworms in duodenum. Conclusion: Hence, severity of anaemia is directly proportional to the number of hookworms in duodenum.