This paper reports on surveys of farmers' seed boxes, which were carried out in the Wimmera and Mallee regions of Victoria in 2001. From seeds ready to be sown, 160 cereal (mainly wheat and barley) and pulse samples (mainly lentils, beans and peas) were collected and the level and species of weed seed were determined. For lentils (28 samples), the seed box survey was followed up with a paddock survey at flowering and the determination of foreign seed material in the final harvested grain. A wide range of weed species was found in the farmer-retained seed. Farmer-retained seed also contained more weed seeds than certified seed. The main foreign seeds in cereals were annual ryegrass ( Lolium rigidum), volunteer canola, volunteer barley, wild oats ( Avena spp.), silver grass ( Vulpia bromoides), volunteer wheat, lesser canary grass ( Phalaris minor), brome grass ( Bromus spp.), volunteer oats and paradoxa grass ( Phalaris paradoxa). For lentils, a number of common weeds were identified which tend to persist in the cropping system and replenish the seed bank. Annual ryegrass was identified as the most problematic weed. Other weeds such as vetch ( Vicia sativa) and bedstraw ( Galium tricornutum) could become serious problems in pulses if effective management practices are not found soon.