This paper presents findings of an acoustic phonetic analysis of vowels produced by speakers of English as a second language from northern India. The monophthongal vowel productions of a group of male speakers of Hindi and male speakers of Punjabi were recorded, and acoustic phonetic analyses of vowel formant frequencies and vowel duration were performed. The results confirm findings of a number of earlier auditory and acoustic studies. A modified inventory of vowel contrasts for the set of monophthongs following Wells' model of standard lexical sets (1982) is proposed to account for vowels produced by speakers of IE whose L1 is either Hindi or Punjabi. Certain features of the vowels produced by speakers in this study are similar to those produced by speakers of IE with other L1 backgrounds. This is particularly evident with reference to the realization of the tense/lax contrast, which can be based on quality and durational differences in some instances, or on durational differences alone. This study also presents some new results, previously not noted in the IE literature, particularly with respect to pronunciation of the central and back vowels.