<p>In this study we set out to calculate the Avogadro number (N_mx) for a set of 22 molecular crystals of known experimental density. Crystals comprise cubic, orthorhombic, and monoclinic unit cells whose lattice parameters are available in the Cambridge Structural Database (CSD). The computed N_mx values are then compared to the modern value of the Avogadro constant (N_A), which is taken as reference. The crystals that yield the N_mx values closest to N_A are characterized by extended networks of hydrogen bonds which are likely responsible for high values of the packing coefficient (PC &gt; 0.7). Thus, crystals with dense packings are likely to produce values of N_mx that converge towards N_A. However, there are exceptions to this trend since some crystals with low PC values (PC &lt; 0.7) yield N_mx values which also are close to N_A. Another surprising result is that concerning a group of tightly packed crystals which produce values of N_mx that are significantly higher than N_A. This result could arise from the low accuracy of the experimental densities utilized herein or from the presence of impurities incorporated into molecular solids during the crystallization process. Thus, the need to perform accurate measurements of the experimental density done at the same temperature as that of the X-ray data collection would be important for assessing the factors that contribute to the deviation from Avogadro constant.</p>