Private sector employment rose by 147,000 jobs in October, falling short of estimates on Wednesday. This marks the smallest increase since May and the third worst report in the past year.
Companies in the private sector were expected to create 165,000 jobs in October, according to economists polled by Reuters.
ADP also revised job creation numbers for other months as part of a new measuring model. For September, the number of total jobs added was revised up to 202,000, from a previous estimate of 154,000. Over the course of a year, the new model subtracted a net of 15,000 jobs.
The new ADP model also shows 32,000 fewer jobs than the number the Bureau of Labor Statistics reported in the private sector over the same period. The old ADP model showed 17,000 fewer jobs than reported by the BLS.
Mark Zandi, chief economist of Moody's Analytics, described job growth in the private sector as "strong," even if the pace of growth appears to be slowing.
"Behind the slowdown is businesses' difficulty filling open positions," Zandi said in a release. "However, there is some weakness in construction, education, and mining."
During the month, small businesses accounted for 34,000 new jobs.
"Job growth appears to be shifting from small to large companies due to the lessening impact the global economic environment had on large companies earlier in the year," Ahu Yildirmaz, vice president and head of the ADP Research Institute, said in a release. "This is also true because large companies often have the resources to attract workers with better pay and benefit packages."
This is a developing story. Please check back for updates.
— CNBC's Steve Liesman contributed to this report.