Ultrathin polyelectrolyte capsules fabricated by stepwise assembly of poly(styrenesulfonate Sodium salt) and poly(diallyldimethylammonium chloride) are examined by confocal laser scanning microscopy and scanning force microscopy. The capsule surface is composed of grains of 124 +/- 10 nm in diameter with a roughness of similar to 13 nm. These grains are formed by laterally segregated polyelectrolyte complexes. Osmotically and annealing-induced capsule swelling facilitated further grain segregation together with a capsule surface area increase. Incubation in salt solution induced capsule shrinking and grain aggregation.