The Second International Workshop on Conversational Approaches to Information Retrieval (CAIR'18) was held on July 12th, 2018 in Ann Arbor, Michigan, USA in association with SIGIR 2018, the 41st International ACM SIGIR Conference on Research and Development in Information Retrieval. CAIR'18 brought together academic and industry researchers to present and discuss new research on conversational approaches to search. This report provides a summary of the workshop consisting of two keynote talks, five oral presentations, and a joint panel discussion with the KG4IR workshop.