Eimeria vilasi and E. beecheyi are reported for the first time from the golden-mantled ground squirrel (Callospermophilus lateralis). Eimeria vilasi was found in 12 of 35 (34%), and E. beecheyi in 2 of 35 (6%), golden-mantled ground squirrels in Arizona. Sporulated oocysts of E. vilasi were ovoidal, 18.1 × 15.8 (15–21 × 13–18) µm, with a length/width ratio of 1.1 (1.0–1.3), and 1–4 polar granules. Sporocysts were ellipsoidal, 10.1 × 6.0 (8–12 × 5–8) µm, with a length/width ratio of 1.7 (1.4–2.2). Sporulated oocysts of E. beecheyi were subspheroidal, 14.8 × 12.9 (14–17 × 12–15) µm, with a length/width ratio of 1.1 (1.1–1.3), and 1–3 polar granules. Sporocysts were ovoidal, 8.1 × 5.1 (7–9 × 4–6) µm, with a length/width ratio of 1.6 (1.4–1.8). The measurements and structural features of these oocysts were similar to those reported for E.vilasi and E. beecheyi recovered from other marmotine rodents. In addition, 20 of 35 (57%) golden-mantled ground squirrels were positive for Eimeria callospermophili, and 3 of 35 (9%) for Eimeria cynomysis, infections.