The water absorption and swelling characteristics along the surface and thickness were determined for particle boards made from coir pith of 0.4, 0.8, 1.2 and 2.1 mm average particle sizes using phenol-formaldehyde and urea-formaldehyde resins. The water absorption, swelling along surface and thickness ranged from 30% to 133%, 0.7% to 3.7% and 24% to 112.6%, respectively. The water absorption and swelling were least for the board made from largest-size particles and phenol-formaldehyde resin.