OBJECTIVES: To compare Finnish patients with erectile dysfunction (ED) and men from the Finnish general population in measures of self-reported Health-Related QOL (HRQoL) and satisfaction with life, and to investigate whether switching patients from current oral ED medication to tadalafil impacts these measures. METHODS: A total of 202 Finnish men over 18 years successfully treated with oral ED prescription medication (tadalafil excluded) voluntarily entered this multicenter, open-label, one-arm, 3-month study. Upon enrollment, patients discontinued their previous therapy and were started on tadalafil 10 or 20 mg (dose determined by investigator) on demand. Outcome was measured using the 15D and Life Satisfaction-11 (LiSat-11) checklists. 15D is a generic, comprehensive, 15-dimensional, standardized, self-administered measure of HRQoL used as both a profile and single score measure. LiSat-11 is a generic validated checklist for self-perceived satisfaction with life. A Finnish, age-matched male population cohort was used for comparison. RESULTS: A total of 194 patients provided data for analysis at baseline and outcome at 3 months. The changes observed (baseline to endpoint) were as follows: average usage of ED tablets per four weeks increased from 4.7 to 9.7, intercourse attempts from 6.4 to 10.6, and the success rate of intercourses from 79% to 92%. At baseline, the 15D score was higher for the study patients than for the comparator population (0.924 vs. 0.902). Nevertheless, significant improvement (baseline to endpoint) was reported on the 15D dimensions of mobility, depression, distress (all p<0.01), and sexual activity (p<0.001); and life in general (p<0.05), leisure (p<0.01), sexual life, family life, and partnership relation (all p<0.001) domains of LiSat-11. CONCLUSIONS: When patients switched from other oral ED medication to tadalafil, improvement was seen in 3 of 15 dimensions of 15D and in 5 out of 11 domains of LiSat-11, including the closeness items: sexual life, partnership relation, and family life.