Transparent exopolymer particles (TEP) are a class of gel particles produced mainly by microorganisms. TEP play an important role in the ocean carbon cycle, affect sea–air gas exchange and contribute to organic aerosols. The first step to evaluate the TEP influence in these processes is the prediction of TEP occurrence in the ocean. Yet, little is known about the physical and biological variables that control their abundance, particularly in the open ocean. Here we describe horizontal TEP distribution in the surface waters along a North–South transect in the Atlantic Ocean during October–November 2014. Physical and biological variables were run in parallel. Two main regions were separated due to remarkable differences; the open Atlantic Ocean (OAO, n = 30), and the Southwestern Atlantic Shelf (SWAS, n = 10). TEP concentration in the entire transect ranged from 18.3 to 446.8 µg XG eq L −1 and averaged 117.1 ± 119.8 µg XG eq L −1 , with the maximum concentrations in the edge of the Canary Coastal Upwelling (CU, n = 1) and the SWAS, but with the highest TEP to chlorophyll a (TEP : Chl a ) ratios at the OAO (CU excluded, average 183 ± 56) and CU (1760.4). TEP were significantly and positively related to Chl a and phytoplankton biomass, expressed in terms of C, along the entire transect. In the OAO, TEP were positively related to some phytoplankton groups, mainly to Synechococcus , and negatively related to the previous 24–hours averaged solar radiation, suggesting the predominance of TEP breaking above the induction of TEP production by UV radiation. Multiple regression analyses showed the combined positive effect of phytoplankton and heterotrophic prokaryotes (HP) on TEP distribution in this region. In the SWAS, TEP were positively related to high nucleic acid prokaryotic cells (HNA) and total phytoplankton biomass, but not with any particular phytoplankton group. TEP constituted an important portion of the particulate organic carbon (POC) pool in the entire transect (28.1–109.8 %), and was generally higher than the phytoplankton and HP fraction, highlighting the importance of TEP in the cycle of organic matter in the ocean.