OBJECTIVE To evaluate factors for associations with duration of first remission and survival time in dogs ≥ 14 years of age with stage III to V multicentric lymphoma. DESIGN Retrospective cohort study. ANIMALS 29 dogs ≥ 14 years of age with multicentric lymphoma treated with a chemotherapy protocol at dosages used for younger dogs (n = 22) or with prednisolone alone (7). PROCEDURES Various data were collected from the medical records, including treatment response and related adverse events. Survival analysis was performed to determine duration of first remission and survival time (from start of chemotherapy), and these outcomes were compared between various groupings. RESULTS The 7 (24%) dogs that received prednisolone alone had a median survival time of 27 days and were excluded from further analysis. Complete clinical remission was achieved in 21 of the 22 (95%) remaining dogs; 1 (5%) achieved partial remission. Median duration of first remission was 181 days. Anemic dogs had a briefer remission period (median, 110 days) than nonanemic dogs (median, 228 days). Median survival time for all 22 dogs was 202 days, with estimated 1- and 2-year survival rates of 31% and 5%, respectively. Six (27%) dogs had adverse events of chemotherapy classified as grade 3 or worse. CONCLUSIONS AND CLINICAL RELEVANCE Survival time was substantially longer in dogs treated with a chemotherapy protocol versus prednisolone alone. Findings suggested that the evaluated chemotherapy protocols for lymphoma were beneficial for and tolerated by very elderly dogs, just as by younger dogs, and need not be withheld, or dosages adjusted, because of age alone.