This study was set out to document the marine algal species associated with limpets living on the rocky shores of the north-eastern coast of Libya for the first time. Samples were collected from seven sites extend from Ras Hailal to Al-Hanyaa rocky shores during winter and spring 2012. Algal species associated with limpets in Al-Hanyaa polluted site were represented by two species belong to Chlorophyta and only one species for each Phaeophyta and Rhodophyta. On the other hand, a single species of Rhodophyta was recorded on Patella turbinata inhibiting the clean site of Susa. The present results showed that, the four algal species comprised Ulva, Enteromorpha, Ectocarpus and Gelidium, were found associated with P. turbinata and were the predominant species in polluted sites, while they disappeared completely at the clean sites. These results predicted that, Boergeseniella fruticulosa, growing either on Patella turbinata or the surrounding substrates, is a promising biomonitor for seawater cleanness. Also, the results confirmed the mutualism relationship between Patella and ephemeral algal species in the monitoring area, emphasizing their efficiency as biological monitors. Finally, in spite of physico-chemical parameters differences between siteswere significant, the diference between sites themselves were found to be non significant.