Anaemia is commonly seen in critically ill patients and is associated with considerable morbidity and worse outcomes. Common factors responsible for development of anemia during their stay in ICU are due to blood loss, nutritional deficiency, drug induced, phlebotomy and defective or decreased erythropoiesis etc. Aims: This study aimed to determine the causes of anemia and to analyzehematological, biochemical, and clinical pathological parameters from ICU patients. Methods and Material: Prospective observational study of 300 adult patients admitted to the ICU with stay of more than 7 days. Details such as age, sex, and clinical history (history of phlebotomy and blood transfusion) was obtained. Hemogram, PBS and other parameters (imaging, biochemistry, microbiology, serology) were studied. Results: Out of the 300 patients discharged with anemia, 266 had anemia at admission and 34 developed anemia during ICU stay. Most common cause of admission to ICU was medical followed by surgery and trauma. 65 patients had shock at admission. Lowest mean Hb was 7.13 g/dl seen in septic cases, most common type of morphological anemia at admission was NCNC. Anemia worsened in 101 patients, with male (64) predominance. 8 patients with worsened anaemia did not survive. Conclusions: Anemia is a significant cause of morbidity in critically ill patients specially in background of sepsis, post operative period and chronic renal diseases.