The Codex Alimentarius approach for risk assessment is followed for Cryptosporidium in water, lettuce and meat. The different elements of risk assessment are described. For water a probabilistic risk assessment is performed taking into account variability. Also a risk assessment is performed based on some worst-case assumptions. An incidentally high contamination level of a raw water source as well as a failing water purification system can directly result in a significant risk of illness. It is recommended to validate the performance of water purification systems. For meat and lettuce only a semi-quantitative risk assessment is possible due to a lack of data. The most important risk factors are given as well as points where data is most needed. Since faecal contamination is the greatest risk factor, all measures taken to minimize this contamination (e.g. application of GAP, use of clean water for irrigation and washing) will also reduce the risk of Cryptosporidium in food stuffs. Quantitative risk assessment is a good tool to predict the effect of control measures. Scenario-analysis with the available data is more important than the absolute results of the risk assessment itself.