The objective of the present study was to analyze levels and distribution patterns of isozyme variation in the only five known populations of Legrandia concinna, a threatened and range-restricted species to the temperate forest of the Chilean South Central Andes. Six enzyme systems were resolved using a combination of two buffer solutions which yielded information on nine putative loci; 67 % of these were polymorphic in at least one population. Levels of genetic variation for L. concinna populations are low, with average polymorphism of 31 %, and observed and expected heterozygosis of 0.07 and 0.11 respectively. We found significant mean within-population inbreeding (F_IS = 0.395) and among-population divergence (F_ST = 41 %). Cluster analysis indicates that genetic diversity is latitudinally structured. Our results show that even small populations may still retain as much genetic diversity as larger ones, which, in addition to significant restrictions for gene flow, call for urgent conservation actions; otherwise L. concinna could be seriously threatened.