We investigated the effect of pelvic floor muscle training on the efficacy of full spectrum therapy and maximal voided volume in children with nocturnal enuresis. We also determined factors predicting treatment outcome, full spectrum therapy duration and the relapse rate. Full spectrum therapy is a combination of alarm, reward, timed voiding and drinking, over learning and pelvic floor muscle training. A total of 63 consecutive children were referred to the physiotherapy department for full spectrum therapy to resolve nocturnal enuresis, including 32 in the experimental group who underwent full spectrum therapy with pelvic floor muscle training and 31 in the control group who underwent full spectrum therapy without training. There was no significant difference in treatment outcome, duration, maximal voided volume and relapse between the 2 groups. Of all children 89% became dry within 6 months. During the year after treatment 33.3% and 37.9% of the experimental and control groups relapsed, while the relapse rate at 1 year was 7.4% and 20.7%, respectively. Age and child motivation were associated with the duration of success (p = 0.04 and <0.01, respectively). Secondary enuresis and psychosocial problems were factors significantly related to relapse (each p <0.01). There is no beneficial effect of including pelvic floor muscle training in full spectrum therapy. Older children and those with better motivation experienced more rapid success. Factors predicting relapse were secondary enuresis and psychosocial problems.