The development of our understanding of astrophysical ices depends on the interpretation of relevant astronomical observations with the aid of laboratory data for interstellar ice analogues. This paper aims to give an overview of current research, with emphasis on recent results appearing since my previous review of the topic (Whittet, 1993). The text is divided into four sections. The introduction highlights the significance of interstellar ices, and provides a historical perspective for current research. A brief review of the technique is presented in Section 2. The observations and their interpretation are discussed in detail in Section 3. This section includes a summary of the latest available data on the all the principal constituents accessible to observation, namely water-ice, alcohols, hydrocarbons, CO, carbon dioxide, nitrogen-bearing and sulphur-bearing molecules. The final section attempts to give a synthesis of our current knowledge, to identify the principal areas of uncertainty, and thus to provide a basis for future research.