Background: School workstations are often inappropriate in not offering an optimal sitting posture. The aim of this study was to investigate the effects of individually adjustable saddle-type chairs with wheels and desks with comfort curve and arm support on schoolchildren's working postures compared to conventional workstations. Methods: Ninety-seven participants aged 12-16 years were followed for 1 year, 47 at an intervention school and 50 at a control school. Anthropometrics and workstation dimensions were measured and working postures analyzed for a part of each group (n=21, both groups) by means of video recording at baseline, before new workstations were introduced, and during follow-up. Results: There was a significant increase in upright back (p = 0.012) and neck (p = 0.019) postures in the intervention group compared to controls during follow-up. The saddle-type chairs allowed significantly greater trunk-thigh angles (p lesser than 0.001) among participants than conventional chairs. Conclusions: In schoolchildren, using individually adjustable saddle-type chairs and desks with comfort curve, a better match between workstations and anthropometric dimensions and improved working postures are obtained than using conventional workstations.