CHIP is a computer program for the automatic coding and analysis of parent-child conversational interaction. The program was developed because manual coding of large collections of computerized transcripts cannot possibly be completed within a reasonable time span. CHIP codes parent-child conversational data as stored in transcript files and computes a series of descriptive statistics based on these codes. Parental responses to child utterances and child responses to parent utterances are both coded. This allows for an analysis of the reciprocal relationship between parental and child language. Three longitudinal corpora from CHILDES (totaling 151,900 utterances) were coded and analyzed by CHIP. The results indicated a high degree of contingency between parental and child language for different word classes across a large span of development. Two main points are argued: (1) Automatic data coding and analysis programs are important new tools for transcript analysis, and (2) CHIP, as an example of such a tool, can provide detailed information concerning the exact nature of parent-child conversational interactions.