This paper describes a teacher-friendly approach to evaluating online mathematics resources. The Alessi and Trollip (2001) evaluation form is recommended as an instrument for assessing the worthiness of online resources from an instructional design point of view. An exploration of nearly 250 mathematics education websites revealed the benefits and limitations associated with using such a checklist. These issues are discussed through screen snapshots of webpages available from the WWW. This exploration also revealed that online resources from professional organisations’ websites seem to be better designed, organised, easy to search and more comprehensive than those from individuals’ websites.