Women are born with thousands of follicles in their ovaries but less than 1% will produce a mature oocyte. What distinguishes the 99% of ovarian follicles destined for demise from the rare 1% that succeed? Here, we leveraged a unique clinical opportunity, paired follicular fluid samples from small antral follicles containing viable and atretic oocytes, to uncover the proteomic determinants governing oocyte fate. Our analysis identified nearly 1,500 proteins, revealing that healthy follicular fluid is enriched with proteins crucial for energy metabolism, antioxidative defense, structural integrity, and robust signaling networks, supporting successful oocyte survival and maturation. In contrast, atretic follicles exhibited a distinct inflammatory signature characterized by acute-phase and immune activation proteins, indicative of active degeneration. These novel proteomic insights deepen our understanding of follicle biology and open new avenues for biomarker development, optimization of assisted reproductive technologies, and targeted therapeutic strategies to preserve and enhance female fertility.