The postharvest onion losses pose a serious challenge to the government in maintaining adequate supply and price. One of the causes of onion deterioration and wastage during storage is rotting, which is brought on by natural decay and bacterial pathogenic infections. Certain volatile organic compounds (VOCs) emitted by onions have been reported to be useful in differentiating between fresh and spoilt onions. This paper reports a chemiresistive based PEDOT sensor to detect onion spoilage with an appreciable sensing response of 30 % with good repeatability and reproducibility.