Hepatic lipidosis or fatty change refers to the accumulation of triglycerides in the cytoplasm of hepatocytes and is a non-specific reversible form of cellular injury that can be physiological or pathological. It represents a challenge in veterinary practice and different fatal syndromes have been associated with hepatic and renal lipidosis in several animals, such as cats, guinea pigs, sheep, cows, ponies, macaques and marmosets. The pathogenesis is not well understood and predisposing factors are variable. The aim of this report is describe for the first time the association of clinical, laboratorial and pathological findings of hepatic and renal syndrome in a marmoset. A 6 years-old, female, 272g, black pincelled marmoset was attended in a private clinic with 3 days of sudden anorexia, vomiting and uncomfortable posture. At the physical examination, the marmoset was in a stupor state, hypothermic, dehydrated and had distended abdomen and abdominal pain, black vomiting and dyspnea. Despite of the intensive care, the animal died 2 days later. Laboratorial tests revealed hipocromic anemia, leucopenia with left shift and relative neutrophilia; lipemia; triglicerydes, creatinine and blood urea nitrogen elevated. Image evaluation showed hepatomegaly and gas dilated intestinal loops. Gross findings were enlarged yellow and tan liver, splenomegaly, enlarged and tan kidney, ulcerative and hemorrhagic gastritis and necrotic esophagitis. Microscopic features were severe diffuse fatty change in the liver, moderated vacuolation and mild necrosis of proximal renal tubular epithelium, and systemic candidiasis. The death was due to metabolic collapse and disseminated yeast opportunist infection. Predisposing factors, such as obesity, anorexia and sudden fasting, and comparison with other species with lipidosis syndrome were considered in order to characterize the process in marmosets. In conclusion, marmosets can develop acute and fatal hepatic and renal lipidosis when submitted to stress, anorexia or sudden fasting. Careful management of stressful situations may be useful in preventing the syndrome and also make a quick diagnosis and treatment available may avoid the death.