Samiabad-e Arbab Din Mohammad () is a city in, and the capital of, Pain Jam District in Torbat-e Jam County, Razavi Khorasan province, Iran. It also serves as the administrative center for Zam Rural District.
At the time of the 2006 National Census, Samiabad-e Arbab Din Mohammad's population was 1,408 in 314 households, when it was a village in Zam Rural District. The following census in 2011 counted 1,862 people in 468 households. The 2016 census measured the population of the city as 1,617 people in 445 households.
The village of Samiabad-e Arbab Din Mohammad was converted to a city in 2017.