Eldritch Moon continues where Shadows over Innistrad left off. It expands its horror theme into Lovecraftian Cosmic Horror. The expansion symbol of the set is a stylized silhouette of Emrakul, but also resembles Liliana's headdress. The set contains 205 cards (74 commons, 70 uncommons, 47 rares, 14 mythic rares), including 15 double-faced cards, 6 meld cards (3 pairs), and randomly inserted premium versions of all cards.^[3] A checklist card replaces the basic land in some boosters.

The set is peculiar in its distribution of colors. Counting cards by their casting cost gives a wildly varying number of cards per color, with white having the most cards (36) followed by Red (35), Black (34), Blue (32) and Green (31). When adding in multicolor cards, Eldrazi using the Emerge mechanic with a colored cost as well as the land Hanweir Battlements which has multiple abilities requiring red mana, the totals even out more: White, Blue and Black have 39 cards each that can be cast using those colors, while Red and Green have 38 each (note that these totals count multicolor cards for each of their colors).

All Eldritch Moon boosters contain 15 cards each.