A total of 62 samples of commercial horse feed preparations (complementary feeds) containing cereal mixtures ("muesli" or mash, n = 39; pelleted feeds, n = 12), and plain horse feed grains (maize, n = 5; oats, n = 4; barley, n = 2) were purchased from 21 different producers/distributors from the German market. All samples were analysed by competitive enzyme immunoassays (EIA) for six different mycotoxins (mycotoxin groups). Analytes (detection limit, mean recovery) were: deoxynivalenol (DON, 10 µg/kg, 84%), zearalenone (ZEA, 5 µg/kg, 93%), fumonisin B1 (FB1, 2 µg/kg, 113%), T-2 toxin (T-2, 0.1 µg/kg, 71%), sum of T-2 + HT-2 toxin (T-2/HT2, 0.2 µg/kg, 97%), ochratoxin A (OTA, 0.2 µg/kg, 67%), and total ergot alkaloids (Generic Ergot Alkaloids "GEA", 30 µg/kg, 132%). All samples contained DON (16-4,900 µg/kg, median 220 µg/kg), T-2/HT-2 (0.8-230 µg/kg, median 24 µg/kg), and T-2 (0.3-91 µg/kg, median 7 µg/kg). ZEA was detected in 98% of the samples (7-310 µg/kg, median 61 µg/kg). Most samples (94%) were positive for FB1 (2-2,200 µg/kg, median 27 µg/kg). Ergot alkaloids were detected in 61% of samples (28-1,200 µg/kg, median 97 µg/kg), OTA was found in 42% of samples (0.2-4 µg/kg, median 0.35 µg/kg). The results demonstrate that a co-contamination with several mycotoxins is very common in commercial horse feed from the German market. The toxin concentrations were in most cases well below the levels which are usually considered as critical or even toxic. The highest mycotoxin concentrations were mostly found in single-grain cereal feed: the maximum values for DON and FB1 were found in maize, the highest T-2/HT-2 toxin concentrations were found in oats, and the highest concentration of ergot alkaloids was found in barley. In composed feeds, no correlation between cereal composition and mycotoxin levels could be found.