Low-grade non-Hodgkin lymphomas were once considered as a heterogenous group of lymphomas characterized by an indolent clinical course. Today, low-grade non-Hodgkin lymphomas are classified as a group of 10 distinct entities, each characterized by unique clinico biologic features. Follicular lymphoma, chronic lymphocytic leukemia/small lymphocytic lymphoma, lymphoplasmacytic lymphoma, and marginal zone lymphoma are the most-investigated subtypes. Several studies have been performed to identify prognostic factors specific for each subtype in an effort to help clinicians in treatment decisions. The field of biologically specific associated parameters holds great potential but requires more research and work to produce translational results.