An improved blowout preventer for a well having a casing extending into an underground formation. The blowout preventer has a pair of opposed ram members received within a pair transverse bores within the main housing. The ram members move between an engaged position wherein they engage the pump rod and each other when a pump rod is received through the longitudinal bore in the housing, and a disengaged position where they are retracted from engaging either the pump rod or each other. There are one or more side entry ports within the main housing which permit a fluid or elongate member to be inserted into the casing.