This study aimed at assessing the chemical composition of the essential oils from leaves and fruits of Conchocarpusfontanesianus, an endemic Brazilian species of Rutaceae. The plant material was harvested from two regions of the Atlantic rainforest in the State of São Paulo. The volatile compounds in the essential oils were extracted by hydrodistillation (HD), and analyzed by GC/FID and GC/MS, allowing the quantification and identification of 54 components in total, which comprise about 97% of the total oil composition. From the leaves collected in Caraguatatuba and Juréia-Itatins, the major volatile compounds identified were as follows: spathulenol (22.32% and 16.67%) and α-cadinol (9.7% and 14.76%). However, β-myrcene (34.56%), (+)-epi-bicyclosesquiphellandrene (8.71%), and bicyclogermacrene (5.80%) were dominant in the fruits collected only in Juréia-Itatins. The invitro biological activities were tested to evaluate the cytotoxic, antifungal, and antioxidant potential of essential oils from leaves and fruits.