Larval and transforming stages of smallscale weakfish Cynoscion microlepidotus (Sciaenidae) are described and illustrated based on samples obtained in three different sites along the Brazilian coast: São Marcos Bay (Maranhão state), Camamu Bay (Bahia state), and the Cananéia-Iguape Estuarine System (São Paulo state). Identification of early stages of C. microlepidotus was based on meristic counts, such as number of myomeres (22), number of fin spines and rays (dorsal XI, 24, anal II, 9 and pectoral 19), morphological features (presence of supraoccipital crest in larvae from flexion to transformation stages, branched anal fin spines) and pigmentation pattern. Early stages of this species are likely to be confused with Carangidae and Scorpaenidae due to the presence of a supraoccipital crest, and with the Sciaenidae species Stellifer rastrifer, Macrodon atricauda, M. ancylodon, and Isopistus parvipinnis due to branched anal fin elements. However, a distinction can be made when analyzing the set of characters (morphology, morphometry, pigmentation) in relation to the different stages of development.