There is limited understanding of the extent to which Mucosa-Associated Lymphoid Tissue (MALT) lymphoma impacts a patient's risk of death and how classically-considered prognostic factors affect lymphoma-specific versus other noncancer mortality. This study analyzed major long-term outcomes of patients with MALT lymphoma and the prognostic significance of baseline clinical features. We reviewed the clinical features, treatments, disease course and survival of 593 patients with MALT lymphoma diagnosed at Memorial Sloan Kettering between 2000 to 2012. Outcomes were analyzed using crude overall survival (OS) and relative survival (RS) by standardized mortality ratio (SMR). The median age was 60 years, 72% were at stage I/II. With a median follow-up of 9.2 years, the 10-year OS, lymphoma-specific mortality and competing non-lymphoma mortality were 75%, 4% and 21%, respectively; the overall SMR was 1.41 (95% CI, 1.19-1.67, P<0.001). Using multivariate analysis, older age, advanced stage and poor performance status were independently associated with inferior OS. Several subgroups had similar RS to the normal matched population, including those with age ≥70, stage I, and skin or gastric origin. Increased lymphoma-specific death was associated with spread disease, while death from non-lymphoma causes was correlated with older age. Overall, a diagnosis of MALT lymphoma was associated with moderately compromised survival. Age and advanced stage emerged as the most important prognostic factors. Younger patients had better OS but worse RS. Disease dissemination was the lymphoma-specific risk factor.