| Official Name: | Pain Marznak |
| Native Name: | پائين مرزناك |
| Settlement Type: | village |
| Pushpin Map: | Iran |
| Mapsize: | 150px |
| Subdivision Type: | Country |
| Subdivision Type1: | Province |
| Subdivision Name1: | Mazandaran |
| Subdivision Type2: | County |
| Subdivision Name2: | Babol |
| Subdivision Type3: | Bakhsh |
| Subdivision Name3: | Babol Kenar |
| Subdivision Type4: | Rural District |
| Subdivision Name4: | Babol Kenar |
| Population As Of: | 2006 |
| Population Total: | 208 |
| Population Density Km2: | auto |
| Timezone: | IRST |
| Utc Offset: | +3:30 |
| Timezone Dst: | IRDT |
| Utc Offset Dst: | +4:30 |
| Coordinates: | 36.3911°N 52.6986°W |
Pain Marznak (Persian: پائين مرزناك, also Romanized as Pā’īn Marznāk) is a village in Babol Kenar Rural District, Babol Kenar District, Babol County, Mazandaran Province, Iran. At the 2006 census, its population was 208, in 50 families.