What was the immediate cause of H.P. Lovecraft's death?

The immediate cause of H. P. Lovecraft's death was terminal cancer of the small intestine.

Lovecraft had long avoided medical attention because of his fear of doctors. He was not examined until about a month before his death, when physicians diagnosed the cancer. By then, the disease was terminal, and he lived in severe pain during his final weeks.

Lovecraft died in Providence, Rhode Island, on March 15, 1937, at the age of 46. Although modern readers sometimes assume that tuberculosis, pneumonia, or a heart attack ended his life, none of those was identified as the cause in the standard biographical account.

His final illness also revealed a striking contrast with his literary interests. Lovecraft maintained a diary describing his condition, reflecting the scientific curiosity that appeared throughout his life and fiction. He was buried at Swan Point Cemetery, where a later fan-funded headstone bears the phrase “I AM PROVIDENCE.”