An in-house-built and designed dilatometer was applied to the study of low profile unsaturated polyester resins. This article first describes the dilatometer used including its calibration then its application to low profile unsaturated polyester resins. Several series of dilatometry experiments were performed, to study the effect of low profile additive concentration and cure temperature on shrinkage control. Scanning electron micro-graphs of the samples were also prepared to show the correlation between shrinkage control and polymer morphology.