The growth of the sweet white lupin industry in Western Australia is a classic case of the adoption and diffusion of a new innovation in agriculture. In 1979, following the release of the cultivar Illyarrie, and the development of effective agronomic practices, the Western Australian Department of Agriculture (Agriculture Western Australia) commenced a major extension campaign to promote lupins. Between 1978 and 1987, the area of lupins grown increased from 39 000 to 877 000 ha. However, the pattern of adoption varied widely between regions, with differences in starting time, rate and ceiling levels of adoption. In this paper, we examine regional differences in the start time of the adoption process, and estimate the impact of various factors by using multivariate regression analysis. Results suggest that both Agriculture Western Australia extension activities and the presence of private consultants contributed to earlier start times of the adoption process.