The interaction between cancer cells and platelets has been known for a long time. Although platelet indices have been also investigated in several clinical settings, it has not been exactly demonstrated in cancer patients. We investigated platelet indices in colorectal cancer patients and compared with healthy subjects. Two hundred and twenty-one colorectal cancer patients and 110 healthy subjects were enrolled into the retrospective study. Data were obtained from computerized medical records of our hospital. Medical record review was performed for all patients regarding thrombocyte indices. Platelet count (325.000/mm3 ± 265.000/mm3 vs 267.000/mm3 ± 67.000/mm3; p=0.025; respectively) and plateletcrit (Pct) (0.25% ± 0.10 vs 0.21 ± 0.05; p<0.001; respectively) were increased in patients compared with healthy subjects while mean platelet volume (MPV) and platelet distribution width (PDW) were similar. The platelet indices were not related to existence of metastasis or acute abdomen. Platelet count and Pct, but not MPV and PDW, are elevated in colorectal cancer patients. Future studies that investigate platelet morphology, function, and putative role of platelets in tumorigenesis and metatasis should be established.