As the climate changes, farmers in developing countries seek to employ strategies to help them sustain food production. The objectives of this paper were to identify adaptation strategies in response to climate change and the determinants for their adoption, and to explore the impact of these strategies on food security. The analysis was based on a survey of 900 small-scale farmers in a semi-arid (Dodoma) and a semi-humid (Morogoro) region in Tanzania. Farmers in the semi-humid region tended to diversify their crops, i.e. added additional crop types. Given the more challenging environment in the semi-arid region, farmers there changed their portfolio of crops, i.e. substituted some crops or cultivars with others. Logistic regressions highlighted higher tolerance to risk, land ownership, education and experiences of farmers as drivers of adoption, while income diversification had a negative effect. The propensity score matching approach showed that adopters of climate-smart strategies are on-average more food-secure. These users showed a more diverse pattern of food consumption, greater protein intake and better economic access to food. Changing crop portfolios can help households to cope with climate-related shocks such as droughts and thus appears to be the best performing strategy, especially in terms of more stable food provisioning throughout the year.