Summary : In the highlands of northern Laos, the Lao-IRRI Project capitalizes on the country's rice biodiversity by introducing superior traditional upland varieties to areas where they are not grown. In so-called "mother-baby-trials", participating farmers run "baby trials" in which they try out a candidate variety, while in the researcher-assisted "mother trial" all of the test varieties are grown side by side to facilitate comparison. Farmers rate the varieties according to agronomic and eating-quality criteria to guide the project's decision on which ones to promote. The project both depends on the genebank near Vientiane for candidate seeds and complements irs conservation effort by keeping worthy traditional varieties alive in farmers' fields.