Background: While tobacco and alcohol studies have focused on density of outlets as a determinant of consumption, research has begun examining the effects of medical marijuana (MM) dispensaries on marijuana use.Objectives: Examine the relationship between density of MM dispensaries and frequency of marijuana use among young adult medical marijuana patients (MMP) and non-patient users (NPU).Methods: Young adult marijuana users (n=329) aged 18-26 years old were sampled in Los Angeles in 2014-15 and separated into MMP (n=198) and NPU (n=131). In 2014, 425 operational MM dispensaries were identified within the City of Los Angeles. Sequential multilevel Poisson random effect models examined density of MM dispensaries per square mile and 90-day marijuana use among MMP and NUP at the ZIP code level while controlling for demographic, behavioral, and community characteristics.Results: Density of MM dispensaries was not related to 90-day use of marijuana (days of use or hits per day) among either MMP or NPU. MMP reported significantly greater days of marijuana