This paper raises awareness of the impact, both positive and negative, of a libraryís information environment on library portal design and usability in terms of information seeking. The authors propose that healthy information environments lay the groundwork for effective end-user searching and browsing. Deficiencies in the information environment place constraints on a library portalís functionality and form, thereby inhibiting searching and browsing. A case study of the McMaster University Library Gateway is put forward to illustrate the influence of a libraryís information environment on portal design and, ultimately, information seeking success. Several recommendations are made on ways to instill healthy information environments which better support a full range of end-user information seeking behaviors. Though libraries may be unable to change all aspects of their information environments, they should be aware of the impact these aspects have on library portal adoption and use and take steps to minimize any resultant negative effects.