This study investigated the effects of board thicknesses and time in service on formaldehyde emission for different wood-based boards sampled from standard particleboard (PB) and medium-density fiberboard (MDF). The test samples were subjected to formaldehyde emission by multi-RAE multiple gas analyzer at a temperature of 20 degrees C and at 65 percent relative humidity for a period of 3 days (Treatment 1 [T1]) and 6 months (Treatment 2 [T2]) after production in accordance with European Committee for Standardization (CEN) EN 13986 and Turkish Standards Institute (TS) EN 717-1. PB with a thickness of 18 mm yielded the highest value of formaldehyde emission (1.1078 ppm for T1; 0.5089 ppm for T2), while 18-mm MDF gave the lowest emission (0.2311 and 0.1378 ppm). After 6 months of production, the reduction was 54 percent for PB and 40 percent for MDF. A significant increase was detected with respect to time in service for all board types, the highest values of formaldehyde emission (1.2900 and 0.5800 ppm) were found in 18-mm PBs that were treated for 3 hours, while the lowest values (0.2433 and 0.1600 ppm) were obtained in the samples of 18-mm MDF that were treated for 1 hour. Accordingly, after 6 months, the reduction in formaldehyde emission was 55 percent for PB and 34 percent for MDF. All values were found above the limits of E1 (<= 0.10 ppm, EN 717-1). In conclusion, thickness, time in service, and type of wood-based boards significantly affect formaldehyde emission.