Longstanding partial edentulism in the posterior segment of the maxilla is a challenging treatment and typically involves extensive and invasive sinus floor augmentation. Various methods have been employed for sinus floor elevation, including the application of hydraulic pressure using the balloon technique. This case report describes a modified ballooning technique to elevate the sinus floor using a Foley catheter to apply the hydraulic pressure method to elevate the Schneiderian membrane prior to the placement of bone grafts and an endosseous implant in a 37-year-old male patient who presented with an atrophic alveolar ridge height of 3.0 mm in the area of the extracted left first maxillary molar. Sinus floor elevation using the Foley catheter led to a sinus floor elevation of 7 mm and a gain in alveolar bone height of 7.8 mm. The patient was asymptomatic with a stable implant during the one-year follow-up period after prosthetic implant loading.