The aim of this study was to survey the content of mycosporine-like amino acids (MAAs) in macroalgae from southern Chile. During the summer 2001–2002, 13 red algal species were collected from the intertidal zone at two sites. All species studied contained various MAA compounds. The concentrations of MAAs in Porphyra columbina were high (7.2–10.6 mg g−1 dw). The second highest MAA concentrations were detected in Gelidium sp. (2.2–6.8 mg g−1 dw), followed by Mazzaella laminarioides (2.1–4.8 mg g−1 dw) and Grateloupia doryphora (3.5–4.4 mg g−1 dw). Six different MAAs (mycosporineglycine, shinorine, porphyra-334, palythine, asterina-330, palythinol) were identified, shinorine being the most common and present in all algae. The two-week period of this study was characterized by high solar irradiance (average daily maxima of UV-B 2.0 W m−2, UV-A 63 W m−2, photosynthetically active radiation wPARx 2263 μmol m−2 s−1 on clear days), which may well explain the high levels of MAAs in these algae. These results are in agreement with others demonstrating the presence of MAAs in various red macroalgae from the eulittoral zone, concentrations generally being higher in geographical locations with high intensities of solar irradiation, which suggests their role as a photoprotective mechanism particularly in this group of algae.