Young children spend a substantial part of their waking time in preschools. It is therefore important to reduce the load of hazardous semivolatile organic compounds (SVOCs) in the preschools' indoor environment. The presence and levels of five SVOC groups were evaluated (1) in a newly built preschool, (2) before and after renovation of a preschool, and (3) in a preschool where SVOC-containing articles were removed. The new building and the renovation were performed using construction materials that were approved with respect to content of restricted chemicals. SVOC substance groups were measured in indoor air and settled dust and included phthalates and alternative plasticizers, organophosphate esters (OPEs), brominated flame retardants, and bisphenols. The most abundant substance groups in both indoor air and dust were phthalates and alternative plasticizers and OPEs. SVOC concentrations were lower or of the same order of magnitude as those reported in comparable studies. The relative Cumulative Hazard Quotient (HQ(cum)) was used to assess the effects of the different reduction measures on children's SVOC exposure from indoor air and dust in the preschools. HQ(cum) values were low (1.0-6.1%) in all three preschools and decreased further after renovation and article substitution. The SVOCs concentrations decreased significantly more in the preschool renovated with the approved building materials than in the preschool where the SVOC-containing articles were removed.