  We classify four-dimensional shrinking Ricci solitons satisfying $Sec \geq
\frac{1}{24} R$, where $Sec$ and $R$ denote the sectional and the scalar
curvature, respectively. They are isometric to either $\mathbb{R}^{4}$ (and
quotients), $\mathbb{S}^{4}$, $\mathbb{RP}^{4}$ or $\mathbb{CP}^{2}$ with their
standard metrics.
