An integral restrictor for capillary supercritical fluid chromatography is described. The device is reproducible, mechanically stable, and can be easily altered to produce a specific mobile phase flow rate. Restrictor design is crucial with regard to detector spiking, particularly for samples containing relatively high molecular weight compounds or polar compounds. The integral restrictor described here demonstrates no detector spiking for a number of chromatographic applications containing both polar and high molecular weight species. Chromatographic separations of samples, including a urine extract, lipids, waxes, and polysiloxane polymers, obtained with 50- and 100-μm i.d. columns and flame ionization detection, are shown. Repetitive injections yielded excellent retention time precision under pressure programming conditions.