Historically, neutropenic sepsis has been associated with high mortality rates. However, there has been limited research into cancer patients admitted with suspected sepsis who are found to be non-neutropenic. C-reactive protein has been shown to be raised in cancer patients for reasons other than infection and there have been limited studies to look as its utility as a prognostic biomarker in suspected sepsis in this population. This study looked at 749 patients admitted to a tertiary cancer centre between January 2015 and February 2016 with suspected sepsis. The neutrophil count and C-reactive protein level was taken in all these patients on admission and at 72 h and compared to the primary outcome of 30-day all-cause mortality rates and hospital length of stay. There were 49 patients who died within 30 days (6.5%). Patients who died were found to have both higher neutrophil counts and C-reactive protein level on admission and at 72 h compared to survivors. Prolonged grade 4 neutropenia was shown to have higher mortality rates. There was only weak correlation between either neutrophil counts or C-reactive protein level and length of hospital stay. This study suggests that higher C-reactive protein level and neutrophil counts and prolonged grade 4 neutropenia are associated with higher mortality rates in cancer patients admitted with suspected sepsis and have utility as prognostic biomarkers in this population.