The influence of life stage on psychosocial adjustment and on factors related to this adjustment was examined in post-operative colorectal cancer patients without stoma. PAIS-SR (Psychosocial Adjustment to Illness Scale-Self-Report) was used to assess psychosocial adjustment, and patients were divided into two groups; a senior group (age > 65 years, n = 34) and a non-senior group (age < 65 years, n = 59) based on cultural features in Japan. Results were compared between two groups for each of the following PAIS domains: "vocational environment," "domestic environment," "sexual relationship," "extended family environment," "social environment," and "psychological distress." Psychosocial adjustment was found to differ by life stage only for "psychological distress" (non-senior vs. senior: 48.6 +/- 9.4 vs. 44.7 +/- 7.7, p < .05). However, analysis of background factors related to psychosocial adjustment revealed distinct patterns in each life stage. This study suggests that life stage should be considered when attempts are made to improve the psychosocial adjustment among cancer patients.