Nine hydrological issues relating to land use and climate change are identified from a southern Africa perspective, each illustrated by an example based on field observations or simulation modelling. The nine issues are that (i) southern Africa's hydrological regime is already so variable that climate change will be difficult to detect; (ii) fluctuations in the hydrological regime are amplified by fluctuations in climate; (iii) hydrological responses are highly sensitive to land use changes; (iv) local scale abrupt land use changes may be hydrologically more significant than regional scale gradual changes; (v) land use change frequently exacerbates already variable flow regimes; (vi) detailed spatial information is vital in assessing impacts of critical land uses; (vii) major components of the hydrological system respond very differently to climate change; (viii) in developing countries inter-seasonal climate change may be more important than that at decadal time scale; and (ix) there is need to identify the hydrologically sensitive areas of a region.