To study the role of the absolute lymphocyte count (ALC), absolute monocyte count (AMC), platelet count (PLT), lymphocyte–monocyte ratio (LMR) and the platelet–lymphocyte ratio (PLR) in the prognosis of primary gastrointestinal diffuse large B cell lymphoma (PGI-DLBCL). We retrospectively analyzed the prognostic value of the ALC, AMC, PLT, LMR, PLR at diagnosis in 173 PGI-DLBCL patients through histopathological examination from March 2009 to February 2015. In total, 173 patients with histopathological diagnosis of PGI-DLBCL in this study, the median age was 51 years (range 12–90 years), median follow-up time was 44 months (range 7–89 months). In univariate analysis, age <60 years, B symptoms, Lugano stage I–II, low international prognostic index (IPI) or low age-adjusted international prognostic index (aaIPI), normal lactate dehydrogenase (LDH), normal β2-microglobulin (β2m), Hb ≥ 11 g/dL, ALC ≥ 1.5 × 109/L, AMC ≤ 0.50 × 109/L, LMR ≥ 2.5, PLR ≤ 170 were related with superior overall survival (OS) and progression-free survival (PFS) (p ≤ 0.05). Multivariate analysis suggested that ALC, LMR, LDH were related with PFS (p ≤ 0.05). Similarly, age and LMR were related with OS (p ≤ 0.05). The parameters (ALC, AMC, LMR, PLR) may be valuable prognostic factors in PGI-DLBCL patients. LMR, PLR at diagnosis are expected to be independent prognostic factors for PGI-DLBCL patients.