This paper examines the impact of information technology-based ridesharing platforms on hospitals' emergency department (ED) admissions. Employing a difference-in-differences design, we analyze patient-level data for 42 million ED visits in Florida. We find that the availability of ridesharing positively affects ED arrivals, indicating enhanced accessibility. Our analysis of the heterogeneous impact of ridesharing suggests the most significant effect applies to young, middle-aged, low-income, and non-critical patients. Additionally, we find a significant increase in ED service time for patients with less critical conditions and no change in visit length for critical patients. The rise in ED demand due to ridesharing entry can have two distinct implications. On the one hand, ridesharing entry addresses the access barrier when the patient's condition is non-critical, but ED usage is necessary. This is a positive impact of ridesharing services availability, especially since it helps low-income communities the most. Therefore, hospitals and ridesharing companies can collaborate to address the healthcare access challenge. On the other hand, ridesharing entry may exacerbate already overcrowded EDs by facilitating non-critical and unnecessary ED usage, which can be an adverse effect. In this case, effective patient triage to identify those with urgent needs may become even more essential after ridesharing entry.