OBJECTIVE The objective is to study the efficacy of fine-needle aspiration biopsy (FNAB) and core-needle biopsy (CNB) in the diagnosis of lymphoma in a single institution. METHODS We retrospectively reviewed 635 FNAB/CNB cases performed in our institution to rule out lymphoma during a 4-year period and collected the relevant clinical and pathological information for statistical analysis. CONCLUSIONS This cohort comprised 275 males and 360 females, with a median age of 57 years. Among the 593 cases with adequate diagnostic materials for lymphoma work-up, 226 were positive for lymphoma, 286 were negative for lymphoma, and 81 were nondiagnostic. Each case had an FNAB, and 191 cases also underwent a CNB. The subclassification rate according to the WHO (2008) was 67% overall, 81% for the FNAB with CNB group, and 40% for the FNAB group. In the FNAB with CNB group, the subclassification rates for cases with and without a history of lymphoma were not significantly different. A definitive diagnosis of lymphoma relied on ancillary studies, but was not affected by location, or the needle gauge of CNB. Follow-up data revealed a high diagnostic accuracy of FNAB with CNB. In conclusion, the use of FNAB and CNB with ancillary studies is effective in providing a definitive diagnosis of lymphoma in our experience at the Northwell Health System.