This paper uses variance decomposition modelling to explore how wheat revenue volatility in Australia has changed spatially and temporally. The components of revenue variance are the variances and covariances of wheat prices, the area of wheat harvested and the yield of wheat. The key finding is that the volatility of wheat revenue (detrended) has more than doubled in every main wheat-growing State in Australia over the last 15 years or so Changes in wheat areas are mostly a minor source of revenue variance. The principal cause of volatility is yield changes with price changes increasing slightly in absolute importance when compared to their adjacent previous period. Greater downside yield risk is often the principal cause of the increased yield variance. The implications are that revenue variance, and especially downside revenue risk, has posed major problems for wheat-dominant farm businesses over the last 15 years or so. How Australia’s wheat producers have managed this greater volatility of wheat revenue is likely to have greatly affected the viability of their farm businesses.