This paper describes a casestudy that investigated students'sociocognitive processes in a multimedia-basedscience learning task. By focusing on students'discursive, cognitive and collaborativeactivity on a micro analytic level, the studydescribes the nature of students' strategicactivity and social interaction whilst handlingand processing information from a multimediaCD-ROM science encyclopaedia. The participantsin the study were eighteen 12-year-old studentsfrom one Finnish elementary classroom workingindividually and in dyads on a poster task. Theresearch data consist of video and audiorecordings, on-line observations, interviews,questionnaires, and assessments of students'poster displays. In addition to cross-analysesof the whole data sample, the results of thestudy are highlighted via three case-basedanalytic descriptions characterising the natureof students' navigation processes, socialinteraction and cognitive activity in themultimedia context. The results of the studyreveal different strategies for informationhandling and processing with multimedia. Thenature of the students' activity show, however,that the cognitive strategies the students usedin processing and handling multimedia-basedscience material and the nature of socialinteractions in which they engaged were ratherprocedural and product-oriented in nature. Thiswas also reflected in the students' posterdisplays indicating rather superficial andincoherent conceptual representations. Thestudy indicates on the whole that moreattention has to be paid to the design ofinstructional situations and pedagogicalsupports for multimedia-based learning.