Purpose <p>To develop a FAP-FDG integrated score (FFIS) based on [⁶⁸Ga]Ga-FAP-2286 and [¹⁸F]F-FDG PET/CT, and evaluate its prognostic value for risk stratification compared to conventional single-parameter imaging.</p> Methods <p>This retrospective study included 193 patients with solid tumors who underwent both [¹⁸F]F-FDG and [⁶⁸Ga]Ga-FAP-2286 PET/CT scans. Overall survival (OS) was the primary endpoint. The FFIS score was constructed by analyzing the uptake intensity and patterns of both radiotracers. Survival analysis employed the Kaplan-Meier method. The prognostic predictive value of FFIS, FDG-SUVmax, and FAP-SUVmax was evaluated using univariate and multivariate Cox proportional hazards models and compared with other clinical variables. Finally, subgroup analysis and interaction tests explored the prognostic consistency of FFIS, FDG-SUVmax, and FAP-SUVmax across different subgroups.</p> Results <p>FFIS emerged as an independent predictor of OS in both univariate (HR = 1.79, <i>P</i> &lt; 0.001) and multivariate (HR = 1.75, <i>P</i> &lt; 0.001) analyses. A higher FFIS reliably predicted worse survival: no deaths occurred among patients of score 1, whereas the median OS was 36, 13, and 8 months for scores 2, 3, and 4, respectively (Log-Rank <i>P</i> &lt; 0.0001). This prognostic stratification remained consistent nearly all clinical subgroups (<i>P</i>-interaction &gt; 0.05). In contrast, FDG-SUVmax showed no independent prognostic value, and FAP-SUVmax was predictive only in univariate analysis (HR = 1.04, <i>P</i> = 0.03).</p> Conclusion <p>By integrating metabolic and stromal information, the FFIS may offer preliminary prognostic value across solid tumors.</p>