The Unconventional Gas Production Revolution in the US has ushered in new opportunities for American petrochemical companies, granting abundant access to gas resources and fostering business growth. Consequently, prominent global petrochemical firms have made substantial investments in the United States' petrochemical and chemical industries. Simultaneously, the surge in gas production from unconventional reserves in the US has led to considerable growth in the country's petrochemical output. To address this crucial topic, we conducted a comprehensive time series analysis, investigating the long and short-term relationships between oil and polyethylene prices in the US during the shale gas development phase. Employing ARDL model for the period spanning from January 2013 to December 2017, our research findings reveal that, in the long run, there exists a positive and significant influence of the oil price variable on polyethylene prices. However, in the short term, no discernible impact on the polyethylene price variable was observed. Interestingly, the analysis also indicates a unidirectional causal relationship, with oil prices influencing polyethylene prices. This finding suggests that despite the divergence between oil and gas prices, oil remains a crucial determinant of petrochemical product pricing.