Strategic IS planning (SISP) is a fundamental tool of strategic IS management. Top management support of SISP, however, is often weak or absent. The association between this support and strategic IS management is important to an understanding of top management’s role in the use of what has been acknowledged as a strategic tool. Strategic use of IS in US electric power companies is noteworthy because the industry is transitioning into a deregulated environment with increasing hostility and can provide special insights not available elsewhere. A postal survey of CIOs and other members of top management from 161 US companies, including 21 electric utility companies, revealed that top management support of SISP is strongly and significantly associated with strategic IS management. Top management support for SISP was present for both electrics and non-electric companies but results were mixed. CEOs exhibited only moderate participation in SISP although such participation was positively and strongly associated with strategic IS management. Overall, results suggest that top management support of SISP may increase when an industry transitions to a more hostile environment. Prescriptions are offered for improving top management support.