Dialogue-based CALL covers applications and systems allowing a learner to practice the target language in a meaning-focused conversational activity with an automated agent. We first present a common definition for dialogue-based CALL, based on three features: dialogue as the activity unit, computer as the interlocutor and negotiation of outcome through open learner production. We conducted a systematic literature review on the main scientific databases resulting, after filtering, in 138 relevant papers, which were analyzed and coded. Results show a scattered research field, with four different disciplinary approaches. We conclude with observations regarding the remaining challenges and opportunities for ICALL research.