Abstract: Bixin is the main carotenoid found in the outer portion of annatto (Bixa orellana L.) seeds. Seed extracts are widely used industrially in pharmaceutical, cosmetic and food formulations as natural dyes to replace chemical additives. Carotenoids are an extensive class of compounds that exhibit low molecular stability due to their chemical structure with conjugated double bonds. Like other carotenoids bixin is unstable in the presence of oxygen and high temperatures, besides being poor-water soluble. Microencapsulation is a technique used to stabilize these compounds and allows a better incorporation of these products in foods, facilitating their handling and minimizing problems of solubility and instability. In the present work, bixin was encapsulated by spray drying using gum arabic as encapsulating agent. Initially, the seeds were characterized in regard to their physicochemical composition. Bixin was extracted from the seeds using a method of successive washes with organic solvents followed by crystallization. Encapsulation was performed using a spray dryer (inlet air temperature 150 oC, outlet air temperature 114 oC, atomizing air pressure 4.9 bar, spray nozzle of 1.5 mm) using gum arabic (30 % w/v) as adjuvant. Particles were characterized spectrophotometrically for the bixin concentration (total bixin and surface bixin), solubility and microstructural aspect. Annatto seeds presented mean percentages of ash, protein, lipid and moisture content of 4.29; 8.98; 1.69 and 11.67 %, respectively. The encapsulation process was feasible and presented an efficiency of 94.8 %. Microscopic analysis showed that particles were irregular in size and shape. The solubility test demonstrated that encapsulated bixin is water soluble, unlike that observed with bixin crystals, which were considered insoluble.