BACKGROUND AND OBJECTIVE: Manifestations of the autosomal recessive disorder lysosomal acid lipase deficiency (LAL-D) include hepatomegaly, elevated serum liver enzymes, and progressive liver disease. We report an analysis of time to progression from first clinical manifestation to first documentation of hepatic fibrosis, cirrhosis, or liver transplantation from an observational study of pediatric and adult patients with LAL-D (clinical trial registration: NCT01528917). METHODS: Data were analyzed from 31 patients with available biopsy data and 1 patient without biopsy data who had undergone liver transplantation. Time to first documentation of fibrosis, cirrhosis, or liver transplantation following the first LAL-D clinical manifestation was estimated using Kaplan-Meier analysis. RESULTS: The median time to an event was 3.1 years. CONCLUSIONS: These findings illustrate the progression of liver damage in LAL-D and the elevated risk for liver transplantation among children and adults with LAL-D.