In this analysis, a semi-distributed conceptual runoff model was applied in five basins varying in area between 43 and 195 km2, lying in different physiographic regions of Switzerland (lowland, alpine, heavily glaciated high alpine basins) representing various runoff regimes. An objective, labour-intensive optimization procedure was developed and found suitable for deriving optimal parameter values. A separate calibration procedure was employed in the heavily glaciated basin, as glacier mass balance data measured at different elevations were deemed very helpful for finding plausible parameter values. The results show that this conceptual runoff model can be successfully applied in various physiographic regions, without structural changes, to calculate daily discharge. However, no conclusive relationships between parameter values and basin characteristics could be found. One reason may be that the investigated sample was too small. It is also felt that the inherent structure of this type of conceptual model is not suited to relating parameter values representing lumped model characteristics with physical basin characteristics. The advantages of conceptual models are such that they can be readily applied in various physiographic regions and therefore constitute a valuable tool for operational hydrology.