This article provides acoustic measurements data for vowel nasalization which are based on speech recorded from fifteen (8 female and 7 male) native speakers of American English in a laboratory setting. Each individual speaker's production patterns for the vowel nasalization in tautosyllabic CVN and NVC words are documented in terms of three acoustic parameters: the duration of nasal consonant (N-Duration), the duration of vowel (V-Duration) and the difference between the amplitude of the first formant (A1) and the first nasal peak (P0) obtained from the vowel (A1-P0) as an indication of the degree of vowel nasalization. The A1-P0 is measured at three different time points within the vowel –i.e., the near point (25%), midpoint (50%), and distant point (75%), either from the onset (CVN) or the offset (NVC) of the nasal consonant. These measures are taken from the target words in various prosodic prominence and boundary contexts: phonologically focused (PhonFOC) vs. lexically focused (LexFOC) vs. unfocused (NoFOC) conditions; phrase-edge (i.e., phrase-final for CVN and phrase-initial for NVC) vs. phrase-medial conditions. The data also contain a CSV file with each speaker's mean values of the N-Duration, V-Duration, and A1-P0 (z-scored) for each prosodic context along with the information about the speakers' gender. For further discussion of the data, please refer to the full-length article entitled “Prosodically-conditioned fine-tuning of coarticulatory vowel nasalization in English”(Cho et al., 2017). Keywords: Vowel nasalization, Coarticulation, Prosodic strengthening, Prominence, Boundary, Phonetic grammar