The coexistence of Planck and Fermi satellites in orbit has enabled the exploration of the connection between the (sub-)millimeter and gamma-ray emission in a large sample of blazars. We find that the gamma-ray emission and the (sub-)mm luminosities are correlated over five orders of magnitude. However, this correlation is not significant at some frequency bands when simultaneous observations are considered. The most significant statistical correlations, on the other hand, arise when observations are quasi-simultaneous within 2 months. Moreover, we find that sources with an approximate spectral turnover in the middle of the mm-wave regime are more likely to be strong gamma-ray emitters. These results suggest a physical relation between the newly injected plasma components in the jet and the high levels of gamma-ray emission.