The deletion of syllable-final consonants in Eastern Andalusian Spanish has been extensively documented; however, there is no consensus about its effect on neighbouring vowels. Researchers have focused on the effects of/s/deletion on vowels to analyse how its semantic value is conveyed, while other consonants which are also deleted have been ignored. This paper examines the effects of word-final/s/, /r/, and /θ/ deletion on preceding /o/ from the point of view of production and perception. Regarding production, acoustic analyses of data from El Ejido (Eastern Andalusia), show specific changes to the F1 and F2 of/o/depending on the underlying consonant it precedes (/s/, /r/, or/θ/). Likewise, a perception test demonstrates that Eastern Andalusian speakers can distinguish between more types of mid back vowels than previously thought.