Seventy-eight cancer patients who were being treated for pain-related problems underwent a semistructured interview concerning the influence of cancer and cancer pain on existential issues. Pain intensity was assessed with visual analogue scales in order to quantify the overall mean pain intensity as well as pain intensity during the best and worst periods. Patients with a higher overall mean pain score (i.e. insufficient pain control) or higher mean worst pain score expressed significantly more fear about the future (P < 0.01), worries about pain progression (P < 0.05) and general anxiety that hampered their daily living (P < 0.05). Younger patients expressed more fear of pain progression and of the future in general and they were much more concerned about the future of their families (P < 0.05). The fear of future pain problems was related to the duration of the pain (P < 0.01). In conclusion, partly unrelieved pain contributes to the 'total pain' experience, not only by causing immediate physical suffering, but also by increasing the anxiety level and the fear about the future and future problems. The study underlines that effective symptom control is a prerequisite for a good quality of life: pain control is a matter of the highest priority.