An immersion lithographic apparatus and method are disclosed in which measures are taken to account for dissolution of resist components, such as photo-acids or photo-acid generators, in immersion liquid. This may involve ensuring that each relevant part of the substrate is covered by liquid the same amount of time and/or by compensating for the differing amounts of time each relevant part of the substrate is covered by liquid by varying exposure intensity or duration based on the amount of time the substrate is covered by liquid.