Free amino acids were analyzed in four macrolichens: Evernia prunastri, Pseudevernia intensa, Flavopuncteliapraesignis and Nephroma resupinatum. Overall concentrations measured fell well within the range of values reported in the literature. Little change in pool size of these amino acids was found in response to sulphur dioxide fumigations. Significant variation among species was observed with the highest values found in the cyanolichen A resupinatum. Species to species variation partly reflected variation in the efficiency of extraction procedures. Because variability was great, relatively few significant differences were found among the amino acid pools observed in the lichen Evernia prunastri and its two symbionts, although higher values of Asp, Asn, Gly and Lys were found in the mycobiont. However, these differences may simply reflect the effects of the media on which the mycobiont was grown