Abstract: There is disclosed a casing centralizer which comprises a pair of longitudinally spaced collars adapted to be assembled about the casing, and bow springs which extend longitudinally between the collars. The ends of the bow springs are secured to the collars by means of outwardly bent portions at the ends of the bow springs which are adapted to fit within openings in the collars, and a tab on one side of each collar opening which extends inwardly from the inner surface of the collar and passes through an opening in the end of the bow spring adjacent its outwardly bent portion, whereby each tab may be bent over the inner surface of the bent portion at the end of the bow spring so as to hold the outer surface of the end of the bow spring against the inner surface of the collar.