| Mariusz Niewiadomski | |
| Height: | 1.83 m |
| Birth Date: | 1959 4, df=yes |
| Birth Place: | Nosówko, Poland |
| Position: | Defender |
| Years1: | 1977–1979 |
| Clubs1: | Gwardia Koszalin |
| Years2: | 1979–1981 |
| Clubs2: | Stilon Gorzów Wielkopolski |
| Years3: | 1981–1988 |
| Clubs3: | Lech Poznań |
| Caps3: | 176 |
| Goals3: | 27 |
| Years4: | 1988–1989 |
| Clubs4: | Polonia Adelaide |
| Years5: | 1989 |
| Clubs5: | Polonia Kępno |
| Years6: | 1990 |
| Clubs6: | Pogoń Szczecin |
| Years7: | 1990 |
| Clubs7: | Vasalunds IF |
| Years8: | 1990–1991 |
| Clubs8: | Hapoel Tel Aviv |
| Years9: | 1992–1993 |
| Clubs9: | Sokół Pniewy |
| Years10: | 1993–1994 |
| Clubs10: | Warta Poznań |
| Caps10: | 32 |
| Goals10: | 2 |
| Years11: | 1994–1996 |
| Clubs11: | Warta Śrem |
| Nationalteam1: | Poland U21 |
| Manageryears1: | –1997 |
| Managerclubs1: | Warta Poznań |
| Managerclubs2: | Lechia Zielona Góra |
| Managerclubs3: | Poznań 2000 |
| Managerclubs4: | Nordenia Dopiewo |
| Managerclubs5: | Aluminium Konin |
| Managerclubs6: | Czarni Browar Witnica |
| Managerclubs7: | Piast Gorzów-Karnin |
Mariusz Niewiadomski (born 26 April 1959) is a Polish former professional footballer who played as a defender.[1]
1981–82, 1983–84, 1987–88