The lumped conceptual rainfall-runoff model NAM was published in Nordic Hydrology (now Hydrology Research) in 1973 in the same issue of the journal as the Swedish HBV model. It was developed at the Technical University of Denmark (DTU), but its worldwide applications can be ascribed primarily to DHI. DHI adopted the model and implemented it in their river modelling software, and it has been used in numerous consulting projects and further developed to become an element in distributed hydrological models.Like HBV, NAM is a soil-moisture accounting model. The overall structure will be briefly presented, and the main difference to HBV highlighted. Also, its role as an element in numerous operational flood forecasting systems worldwide and, more recently, as part of DHI’s global hydrological model will be touched upon. Finally, a discussion of recent developments of machine-learning based rainfall-runoff models will be discussed, which perhaps will bring the era of the lumped conceptual rainfall-runoff models to an end.