A well treating composition of a composite containing a scale inhibitor adsorbed onto a water-insoluble adsorbent is useful in the control, formation and treatment of inorganic scales in a subterranean formation or wellbore. In addition, the well treating composition is useful in controlling the rate of release of scale inhibitor in the wellbore. The water-insoluble adsorbent may be activated carbon, silica particulate, precipitated silica, zeolite, diatomaceous earth, ground walnut shells, fuller's earth and organic synthetic high molecular weight water-insoluble adsorbents. The composite may be introduced into an oil or gas well with a carrier fluid.