Purpose: The purpose of this study was to assess the temporal stability of 5 independent measures of phonological skill: phonetic inventory (initial, final), word shape, syllable structure level, and the index of phonetic complexity. Method: Ten toddlers with typical development participated in two 20-min play sessions within a 1-week period. Test-retest reliability for each measure was determined. Results: Syllable structure level and index of phonetic complexity achieved high test-retest reliability. Word-final phonetic inventory and word shape analyses had moderate but not significant reliability. Word-initial phonetic inventory was not reliable. Discussion: Twenty-minute conversational speech samples were insufficient to obtain reliable results for all measures. Practitioners may want to obtain more extensive sampling when using a phonetic inventory for diagnosis or progress monitoring purposes. Reliable measures within the constraint of a 20-min session, syllable structure level and index of phonetic complexity provide summarized information concerning the phonetic and syllabic characteristics of a child's speech. Syllable structure level places less emphasis on accurate phonetic transcription, making it a good option for speech that is difficult to transcribe.