Heparin induced thrombocytopenia and thrombosis is associated after several days of ongoing heparin treatment. It is an immune-mediated response which leads to life-threatening thrombosis. Thrombocytopenia is caused by presence of antibodies which activate the heparin and bind to platelet factor 4(PF4). HIT is associated with thromboembolic complications in both arteries and venous circulation. Complications such as pulmonary embolism, myocardial infraction, and death due to thrombotic occlusion in heart, lungs and brain. The main diagnostic criteria are to examine the thrombocytopenia during heparin treatment. HITTS mostly occur after 1-2 weeks after the HIT. A complete watch on platelet and laboratory parameters is essential. The treatment options for HITTS are low molecular weight heparin (LMWHs) and antiplatelet agent are provided. The main consequence would be only keeping eye at patient during thrombocytopenia as it leads to thrombosis and providing effective treatment.