ABSTRACTNadroparin, a low molecular weight heparin, has prophylactic and therapeutic use in thromboembolic disorder. In a patient with carcinoma ovarystage 3 B, nadroparin was given prophylactically for deep vein thrombosis (DVT) before and after interval cytoreduction surgery. Nadroparin 0.3 mlwas given subcutaneously once daily for 1 day preoperatively and 8 days postoperatively. Rise in serum potassium was observed on the third postoperativedaysuggestiveof hyperkalemia.Intravenousfluids weregiven,and thedrug wasstoppedon the 9 post-operative day and hyperkalemiaresolved after 2 days. Monitoring of serum potassium level is essential when Nadroparin is administered prophylactically for more than 7 days forDVT. As this case illustrates a causal relationship between nadroparin and hyperkalemia, caution must be exercised with nadroparin.Keywords: Nadroparin, Hyperkalemia, Thrombosis.t