Background: We studied the value of a proposed prognostic index (PI) generated by baseline absolute monocyte (AMC) and lymphocyte (ALC) counts for pts with DLBCL, using values as previously reported (Leukemia 25:1502-9, 2011). Methods: From 03/07 to 01/09, 245 consecutive pts with untreated DLBCL receiving standard R-CHOP from the MDACC database were evaluated. Baseline AMC and ALC were retrospectively recorded. High AMC (≥610/uL) and a low ALC (≤1000/uL) were examined as dichotomized variables for progression-free (PFS) and overall survival (OS). An AMLPI was generated, stratifying pts into 3 risk groups (RGs): low-(AMC <610/uL and ALC >1000/uL), intermediate-(AMC ≥610/uL or ALC ≤1000/uL), and high-risk(AMC ≥610/uL and ALC ≤1000/uL). The prognostic effect of the AMLPI and the IPI were examined by multivariate analysis (MVA). Results: Ninety (37%) had high AMC and 71 (29%) had low ALC. By univariate analysis, a high AMC was associated with inferior PFS (p=0.01) and OS (p=0.03). The frequencies of AMLPI RGs were: low-105 pts (43%), intermediate-119 (48%), and high risk-21 (9%). With a median follow-up of 22 months (range <1-42), 3-year PFS and OS rates for these RGs were 80%, 61%, and 46% (p=0.007) and 92%, 76%, and 60% (p=0.006), respectively. Three-year PFS rates for IPI 0-2 and 3-5 RGs were 73% and 58%, respectively (p=0.0004); comparable OS rates were 88% and 68%(p<0.0001). For pts with IPI 0-2, 1-year PFS rates for AMLPI low, intermediate, and high RGs were 92%, 89% and 80% (p=0.022); comparable 1-year OS rates were 96%, 95% and 80% (p=0.049). By MVA, AMLPI effect (low vs. high RGs) on PFS was significant (p=0.046) as was IPI effect (0-2 vs 3-5, p=0.005); similar results were observed for OS (p=0.052 and p=0.003, respectively). Conclusions: Baseline AMC and AMLPI are significant variables for PFS and OS for pts with DLBCL receiving R-CHOP. AMLPI can identify pts with low, intermediate, and high-risk disease for PFS and OS, particularly for those with IPI 0-2. AMLPI may also add prognostic value beyond that of the IPI.