An object-oriented design methodology for web applications (OODM) was proposed because before this methodology (OODM), all hypermedia methodologies did not differentiate between design phase and implementation phase and there was no or minimum analysis phase in these methodologies. In other words the principles of software engineering were not followed. Security issues were not addressed in OODM. In this paper, security aspects of web applications are included in OODM and its extended version with security model is referred to as the Secure Object-Oriented Design Methodology (S-OODM) for web applications. The working of S-OODM through a case study and security aspect in the design are highlighted.