This study investigated the association of fatigue and cognitive complaints among employees post-cancer diagnosis, with work-related outcomes, and moderation by cancer-related anxiety. A survey was carried out among workers 2–10 years after cancer diagnosis. Employees without cancer recurrence or metastases were selected (N = 566). Self-reported fatigue and cognitive complaints were classified into three groups. ANOVA’s and regression analyses were used, controlling for age. Group 1 (cognitive complaints, n = 25, 4.4%), group 2 (fatigue, n = 205, 36.2%), and group 3 (cognitive complaints and fatigue, n = 211, 37.3%) were associated with higher burnout complaints and lower work engagement, and group 2 and 3 with lower work ability. Cancer-related anxiety positively moderated the association of group 3 with higher burnout complaints. Employees with both fatigue and cognitive complaints report less favorable work functioning. Cancer-related anxiety needs attention in the context of burnout complaints.