Harvey Weinstein claims the New York prison where he's doing time is failing to provide him the medical care he needs ... to the point where he fears for his life.

The disgraced movie mogul just filed a claim with the Office of the NYC Comptroller, alleging the conditions at Rikers Island are making his laundry list of medical issues even worse.

In the docs, obtained by TMZ, Weinstein claims his medical conditions deteriorated significantly and dangerously during his incarceration at Riker Island ... and he's blaming it on the prison.

Weinstein says the prison knows he suffers from leukemia, diabetes, coronary artery disease, obstructive sleep apnea, thyroid issues, obesity, high blood pressure and more ... and he claims the care he's getting falls below the standard of care.

HW says he's suffered significant and ongoing physical and psychological injuries, emotional distress, loss of enjoyment of life ... and wants at least $5 million in damages.

In a statement, Weinstein's attorney Imran H. Ansari tells TMZ ... "Harvey Weinstein has suffered considerably from the deplorable conditions on Rikers Island. ... When I last visited him, I found him with blood spatter on his prison garb, possibly from IV’s, clothes that had not been washed for weeks, and he had not even been provided clean underwear – hardly sanitary conditions for someone with severe medical conditions and susceptibility to illness."

Ansari adds ... "I questioned whether I was in a prison facility that is supposed to be managed in accordance with our constitution, or a gulag where the prisoners are treated like animals."