Bovine eimeriosis is considered to be of considerable importance for the productivity and health of cattle worldwide. Despite the importance of cattle farming in Austria, little is known in this country about the abundance and distribution of bovine Eimeria spp. The objective of this study was to obtain detailed information about the occurrence of different Eimeria spp. on Austrian dairy farms. Fecal samples from individual calves (n = 868) from 296 farms all over Austria (82 districts) were collected. Additionally, each farmer was questioned about the occurrence of calf diarrhea, and about the knowledge on coccidiosis and possible control measures. On 97.97% of the investigated farms, calves excreted Eimeria oocysts, and 83.67% of the individual samples were positive. After sporulation of positive samples pooled from each farm, 11 Eimeria species were found, with E. bovis (in 65.54% of the samples and 27.74% of the farms), E.zuernii (63.85%/13.86%), E. auburnensis (56.76%/13.41%) and E. ellipsoidalis (54.05%/14.38%) being the most prevalent, followed by E. alabamensis (45.61%/11.56%), E. subspherica (35.14%/5.5.05%), E. cylindrica (33.11%/7.00%), and E. canadensis (31.08%/7.74%). E. wyomingensis, E. pellita and E. bukidnonensis were only found sporadically (3.04-4.73% of the samples and 0.16-0.59% of the farms). Mixed infections were present on all farms (2-9 Eimeria species/farm). Prevalences by state provinces were high throughout with 77.1-87.9% of the samples and 93.8-100% of the farms. Lower Austria had the highest percentage of positive farms, and Vorarlberg the lowest. Individual OPG (oocysts per gram of feces) values were generally low; 75% of the samples had an OPG of 1,000 or less. The highest detected OPG was 72,400. The mean OPG was 2,525 with above average numbers in Tirol, Carinthia, and Lower Austria. The mean OPG values were significantly positively correlated with the cattle density in the different districts. The majority of the samples were from female Simmenthal calves. Clinical coccidiosis (diarrhea) was observed in 74 cases, and (semi-)liquid diarrhea (56 animals) was significantly correlated with OPG (p < 0.05). Linear regression on the OPG data showed that OPG values significantly decreased with increasing age of the calves, while the percentage of positive samples increased with age (p < 0.05 for both). The term "coccidia" was familiar to 45% of the farmers, and anticoccidial treatment was performed by 13.51% of them, most commonly with toltrazuril. Considering the ubiquitous occurrence and the possible clinical and economic relevance of calf eimeriosis, infections should receive increased attention by both farmers and veterinarians.