We examined the associations between frailty and inflammatory markers, in particular neutrophil lymphocyte ratio (NLR), in elderly cancer patients. We conducted cross-sectional analyses of data derived from the Carolina Seniors Registry (CSR), a database of geriatric assessments (GA) in older adults (≧65 years) with cancer. We included patients in the CSR who had a GA and complete blood count test before initiation of therapy. The primary outcome was frailty, determined using the 36-item Carolina Frailty Index (CFI). In our sample of 133 patients, the median age was 74, and 54% were robust, 22% were pre-frail, and 24% were frail. There was a significant positive correlation between CFI and NLR (r = 0.22, p = 0.025). In multivariable analysis, patients in the top tertile of NLR had an odds ratio of 3.8 (95% CI = 1.1-12.8) for frail/pre-frail status, adjusting for age, sex, race, education level, marital status, cancer type and stage. In bivariable analyses, higher NLR was associated with lower instrumental activity of daily living (IADL) score (p = 0.040) and prolonged timed up and go (p = 0.016). This study suggests an association between frailty and inflammation in older adults with cancer.