Evaluation of six maize varieties under four different water harvesting and tillage technologies was undertaken with the aim of determining their effect on the performance of maize genotypes and their effectiveness in improving nutrient and water use efficiency. The work was carried out at Mariakani site (one of the KARI centres) representing the arid and semi-arid lands of coastal Kenya in the long rains and short rains seasons of 2005 and 2006 respectively. The results indicate that rainwater harvesting is not critical when the season is wetter than normal in the arid and semi-arid environments. This was demonstrated by the high yields that were recorded from the maize varieties (Pwani Hybrid 4-PH4, Coast Composite Maize-CCM and the local check-Mdzihana) which usually require relatively high rainfall amounts in order for them to produce better yields. Despite the excellent performance of PH4, CCM and Mdzihana, these maize varieties cannot be recommended for the semi-arid areas since the high yields were realized under above normal rainfall. There is need for further research to identify the maize varieties that would be appropriate for the areas that normally receive low rainfall.