Michelle Trachtenberg's Cause of Death Revealed

Michelle Trachtenberg's cause of death is official ... with NYC authorities saying she died from complications of diabetes.

The actress -- who passed away in February -- died from "complications of diabetes mellitus" according to the medical examiner, who cited lab results. Diabetes mellitus is the more technical name for diabetes. It doesn't denote whether Michelle had type 1 or type 2.

The ME is classifying Michelle's death as "natural" ... meaning the investigation into Michelle's death is pretty much closed at this point.

As we told you ... Michelle's mother found her unresponsive after spending the night at her New York City apartment earlier this year. Paramedics were called, but they pronounced Trachtenberg dead at the scene.

We knew Michelle had a liver transplant in the leadup to her death ... and, according to the Health Resources & Services Administration, about 20% of liver transplants in 2023 were done on patients with fatty liver disease -- a condition linked to diabetes and obesity. It's unclear if that is the reason Michelle underwent the procedure.

Many of Michelle's costars and fans paid tribute to her after she passed ... including Sarah Michelle Gellar, Blake Lively, Alyson Hannigan, Kenan Thompson and many other well-known stars.

Trachtenberg starred in classic Nickelodeon projects like "The Adventures of Pete & Pete" and "Harriet the Spy." Her family declined to have an autopsy done on her body, citing religious reasons after she passed.

She was 39.