OBJECTIVE: To obtain data on conventional artificial filling cystometry and ambulatory monitoring in healthy asymptomatic control populations. SUBJECTS AND METHODS: Seventeen healthy volunteers were assessed by means of artificial filling cystometry (CMG), filling at rates of 50 ml/min (CMG 50) and 100 ml/min (CMG 100), and ambulatory monitoring (AM). RESULTS: Significant differences were found between AM and CMG with respect to: the pressure rise on filling (P < 0.02), voided volumes (P < 0.01) and maximum detrusor pressure on micturition (P < 0.01). Detrusor instability was found in 38% of volunteers on AM, in 17% on CMG 50, but in none on CMG 100. CONCLUSION: A range of baseline urodynamic values has been established which could provide the basis for future studies of ambulatory monitoring.