The nasalance score measured by Nasometer is a supplementary data for the perceptually rated nasality by a trained speech pathologist. Because the nasalance score varies with speech material, a valid and reliable material should be developed for evaluating it. The objectives of the present study were (1) to examine whether phonetic contexts affect the nasalace score and (2) to examine the reliability of both meaningless one-syllable words and meaningful sentences. This study analyzed nasalance score in 20 different phonetic contexts from 24 normal adults. The results showed (1) nasalance score increased as the percentage of nasal consonants and vowel /i/ increased, (2) the manner and the place of articulation in oral consonants did not influence the nasalance score, and (3) in nasalance score, correlation between sentences was found to be high, but correlation between syllables was not. These results may indicate that, when preparing the speech material for measuring the nasalance score, it is important to consider not only the percentage of nasal consonants but also that of vowel /i/ in the speech material. In addition, the sentence is more reliable material than meaningless one-syllable words.