A new species of yeast, belonging to the genis Cryptococcus, and namedCryptococcus terricolusnov. spec., was recently isolated from different Norwegian forest soils (Pedersen 1958). Besides being of taxonomic interest, this yeast was found to produce lipids in great quantities. The presence of lipids could easily be estahlished by microscopical examination, owing to the formatinn of a large lipid globule in every cell. In the present paper, investigations on the growth conditions of the organism are presented. The factors influencing the lipid synthesis will be treated in a future article.