This paper first presents an overview of the concepts of assessment and evaluation in Open and Distance Learning (ODL) environment. The large numbers of students and numerous courses make assessment and evaluation very difficult and administrative nightmare at Distance Learning (DL) institutions. These challenges informed exploring issues relating to assessment and evaluation like the development and use of question bank and deployment of technology in assessment with emphasis on strategies for sustainability. Assessment in ODL, unlike in the Conventional system where students have a range of opportunities to demonstrate their learning periodically, depends on formal assessment tasks only. Thus, for validity to be high in ODL assessment, assessment must provide the appropriate situation possible for measuring the specific abilities being measured. Reliability is maximized when the assessment items are many; the items are not too easy or too difficult for the candidates; and the marking consistent. Evaluation depends on Tutor Marked Assignments (TMAs) and End of Semester Examination (ESE) in ODL system. Large question/item bank (with reliable and valid questions) from which items are picked to constitute test are needed. Attempts are made to provide argument for the use of computer as a viable option for sustainable assessment based on its sustainable features especially for ODL institutions with a large number of students' population. It is hoped that these strategies if adopted have the potentials to eliminate some of the challenges that ODL institutions are currently facing in assessment. It will also strengthen quality assurance mechanism in ODL institutions.