Various yeasts and filamentous fungi are described as the cause of infection in sea turtles. Among them, Fusarium solani is responsible both for superficial and invasive infection in weakened adults (capture, stranding), and wild nest contamination, causing massive losses during hatching. We illustrate the pathogenicity of this fungus in sea turtles, through our experience with the species Caretta caretta (loggerhead turtle) and its reproduction, which was obtained for the first time in 2010 at the marine park Marineland, Antibes and renewed in 2011 and 2013. The first generation (6 viable newborns e.g. 0.9% of the nest) was severely affected by an infectious agent causing skin and multifocal organ lesions. Microbiological samples allowed to establish F. solani as the etiological agent. Antifungal therapy with posaconazole cured 2 (33%) of the brood. Epidemiological investigations, infection control and hygiene measures as well as diagnosis criteria, preemptive and curative treatment procedures allowed better prevention and cure and finally higher survival rates in subsequent broods, in 2011 and 2013 (80 viable newborns e.g. 6.6% of the nest and 50% survival rate). F. solani appears as a major threat for the successful reproduction of sea turtles in the wild. As observed, this threat is also of concern during captive breeding. The conditions of transmission and pathogenicity of Fusarium spp. in these animals are discussed in light of the literature cases that occurred in adult sea turtles and in wild nests, and of our breeding experience.