This paper examines the acquisition of English fricatives and is a preliminary report on one aspect of the Child Phonology Project at Stanford University. A characterization of English fricatives is presented, followed by a summary of current information on their acquisition. Three sample hypotheses from the Stanford project are discussed in connection with experimental data: (1) phonemic perception of a voiceless-voiced pair of fricatives implies phonemic perception of a voiceless-voiced pair of stops or affricates at the same place of articulation; (2) errors in the production of fricatives will be in the direction of less marked counterparts; and (3) acquisition of the oppositions /k-g/ and /f-v/ precedes acquisition of voiceless and voiced /kh/, which precedes acquisition of voiceless and voiced /th/. Overall results seem to confirm numbers 1 and 2 but not 3. On the basis of previously available information and new data, a number of general observations are made about the phonological development of fricatives. Although the findings of this paper are tentative, it is hoped they may stimulate further study of language behavior. (Author/AM)