Cassava (Manihot esculenta, Crantz) is perhaps one example of a crop exceptionally adapted to marginal conditions, although it too performs poorly in extreme soil acidity conditions. The differential response of cassava cultivars to high levels of KCl‐extractable soil Al in a Typic Tropudult of Panama is reported in this study. High levels of soil Al reduced plant height and root yields of most cultivars, although some genotypes showed good potential to produce acceptable root yields at Al levels above 5 cmol (p+)/kg. Cultivars showed distinctive leaf area indices (LAI) and leaf area distribution patterns that in some cases appeared to be Al toxicity related. Two possible ways Al might have affected LAI, leaf area distribution and hence root yields are suggested: 1) impairment of its ability to develop and sustain leaf area, and 2) disturbance of its capacity to distribute and accumulate assimilates by roots.