Changes in morphology and sporulation were investigated in liquid cultures of Penicillium chrysogenum P2 supplemented with carbohydrate oligosaccharides. Sodium alginate and locust-bean (Ceratonia siliqua) gum-derived oligosaccharides were used as elicitors. Spore germination was inhibited by the addition of OG (oligoguluronate) elicitor (30% inhibition when compared with control). Addition of any of the elicitors to stirred-tank cultures increased hyphal-tip numbers, clump area and spore counts. MO (mannan oligosaccharide) had the greatest effect on the parameters studied, followed by OM (oligomannuronate) and OG. Hyphal-tip numbers increased by 19, 29 and 47% with OG, OM and MO respectively. Average clump area in the presence of OG, OM and MO increased by 23, 32 and 59% respectively. A notable increase in spore numbers was observed in all the supplemented stirred-tank reactor cultures, with MO showing the highest enhancement.