A study aimed at assessing diversity and local conservation strategies for on-farm woody plants (OFWPs) under different cropping systems was conducted in Nebbi District, north-western Uganda in 2004. Forty farmers were randomly selected and interviewed on local conservation practices of OFWPs. One field per interviewed farmer was randomly selected and woody plants enumerated. On-farm plants’ diversity was calculated using the Shannon–Weiner Diversity Index (H′). Results indicate that >87% of the OFWPs, majority being indigenous species, were utilized. The highest proportion of OFWPs was retained for poles, shade, fruits and medicine. The OFWPs were conserved by deliberately retaining them while opening the field. Woody plant diversity varied between field types. Fields associated with continuous cropping (H′ < 1.7) were less diverse than those associated with fallows (H′ > 1.7) as fallows allow species to regenerate. Poor access to planting materials of OFWPs, inadequate training on nursery techniques, lack of adequate extension services and markets for indigenous woody products limited their conservation. Farmers need to be trained on tree nursery techniques and provided with relevant extension information in order to diversify the production of OFWPs.