We introduce the development of the Electronic Lexicon of Contemporary Newborn Chinese Words: (1) the definition of a newborn word, (2) the main principle behind constructing the lexicon, (3) the collection of newborn words and their feature descriptions of them, and (4) the classification of 40,000 newborn words. In our opinion, a new bornword is a character string that appeared after 1978 in a new form, with a new meaning and with a new usage. In addition, it must be frequently used and accepted, but the names of men and places are not newborn words according to our definition. The approach to collecting newborn words is quite unrestricted, that is, the more the better. Based on the Contemporary Chinese Grammatical Knowledge Base of the Institute of Computational Linguistics at Peking University, we have finished compiling a lexicon of almost 40,000 newborn words semi-automatically. The lexicon, we believe, is a worthy resource for research on Chinese word-building rules and Natural Language Processing. Firstly, classification is done based on the preponderant grammatical characteristics of each word, and then the detailed features are described in the database of ACCESS. The lexicon contains a total base and three grammatical bases (i.e., a noun base, verb base and adjective base); what’s more, it also has an old word base, a loanword base and a acronym base. The entire base is related to the sub-bases through the fields of word, phonetic notation and semantics fields, which form a hypernymy hierarchy that is quite convenient for searching. Totally, there are more than 200 fields in the bases that give information regarding phonetic notation, semantics, sources, word building, syntax and pragmatics. Without doubt, this lexicon is one of the largest domestic lexicons available with the most detailed descriptions of newborn Chinese words.