Forty normal children aged 3 and-one-half to 5 and-one-half were tested on the pronunciation of initial /-1/, /-r/, and /s-/ clusters in 120 words, occurring 36, 48, and 42 times, respectively; other phonemes in the cluster occurred from 6 to 18 times. Articulation errors of individual subjects were examined for evidence of (1) degree and type of consistency, including consistency in rate of error; (2) mispronunciation of a phoneme, unconditionally or in any cluster environment; (3) the articulatory feature changed in substitution errors, regardless of phoneme; and (4) the error made on a phoneme. Results showed that children typically made the same number of errors when retested on similar lists, but not on the same items. There was little evidence for consistency in making errors on particular phonemes or features. Few children mispronounced any phoneme more than 50 percent of the time; most missed a phoneme in initial or final position in a cluster only once. In the few instances in which children made more than one error on a phoneme, the error made was usually the same; that is, the subjects were consistent in the error made. Tables and references are included. (Author/VJ)