Essentially any concept of risk is built on fundamental concepts of chance, likelihood or probability. Although risk is generally a probability of loss of something of value, given that a risk-generating event will occur or has occurred, it is ironic that the quality risk management literature and guidelines on quality risk management tools are relatively silent on the meaning and uses of “probability.” The probability concept is typically applied by risk managers as a combination of data-based, “frequentist” measures of probability and a Bayesian, “degree of belief” meaning of probability. Probability as a concept that is crucial for understanding and managing risk is discussed though examples from the most general, scenario-defining and ranking tools that use probability implicitly to more specific probabilistic tools in risk management. A rich history of probability in risk management applied to other fields suggests that high-quality risk management decisions benefit from the implementation of probability concepts in both risk modeling and risk management.