In the present study, four species of marine algae were collected during different seasons for one year (September 2013 to August 2014). The collected species belonged to Chlorophyta (Ulva lactuca), Phaeophyta (Sargassum denticulatum, Hormophysa triquetra) and Rhodophyta (Hypnea cornuta) in addition to one blue- green alga from freshwater (Spirulina platensis) was obtained from stock at Hydrobiology Lab, Qanater, Khayria, Qalubia, Egypt. Crude algal extracts were prepared by using different solvents (methanol, ethanol and chloroform) in addition to hot water and cold water extracts. The crude algal extracts were examined for their antifungal efficacy against oral Candida species (Candida albicans, C.tropicalis,     C.krusei and C.glabrata) using agar well diffusion method. Results revealed that methanol was the best solvent suited for extraction of bioactive compounds from the tested algae. Chlorophyta (ulva lactuca) exhibited the highest antifungal effect followed by Phaeophyta, Rhodophyta and blue green algae. MIC of the most potent algal (ulva lactuca) methanol extract was 62.5 mg/ml and MFC was 125mg/ml for the same alga with all the tested oral Candida species. (comparison was made between MFC value of Ulva lactuca methanol extract with the anti chlorhexidine (0.1mg/ml)(which is a common antimicrobial agents in commercialized oral rinses). by using (PIDG) .The results shown that the Ulva lactuca methanol extract better than PIDG of chlorhexidine.