A partial synthesis of kaurenoic acid 1 from the hydroxy acid 3 is described. The hydroxylation of the 2′-carboxyethyl ester of 1 by Gibberellafujikuroi has been utilized for the synthesis of 7β-hydroxykaurenoic acid 2. An alternative synthesis of 2 is provided by the microbiological conversion of 3 to the 7β-hydroxy derivative by Calonectria decora.