| Position: | Centre |
| Shoots: | Left |
| Height Ft: | 5 |
| Height In: | 10 |
| Weight Lb: | 165 |
| Birth Date: | August 31, 1959 |
| Birth Place: | La Sarre, Quebec, Canada |
| Played For: | Buffalo Sabres Los Angeles Kings EHC Kloten |
| Career Start: | 1979 |
| Career End: | 1994 |
| Draft: | Undrafted |
Robert Julien Mongrain (born August 31, 1959) is a Canadian former professional ice hockey centre. He played in the National Hockey League with the Buffalo Sabres and Los Angeles Kings between 1979 and 1986. The rest of his career, which lasted from 1979 to 1994, was spent in the minor leagues and then in the Swiss Nationalliga A. After his playing career Mongrain became a coach in the Quebec Major Junior Hockey League, Canadian university leagues, and in Switzerland.
In his NHL career, Mongrain appeared in 81 games. He scored thirteen goals and added fourteen assists.
| Regular season | Playoffs | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Season | Team | League | GP | PIM | GP | G | A | Pts | PIM | |||||
| 1975–76 | Cap-de-la-Madeleine Barons | QJAHL | — | — | — | — | — | — | — | — | — | — | ||
| 1975–76 | Trois-Rivieres Draveurs | QMJHL | 1 | 0 | 0 | 0 | 0 | — | — | — | — | — | ||
| 1976–77 | Cap-de-la-Madeleine Barons | QJAHL | 60 | 53 | 79 | 132 | — | — | — | — | — | — | ||
| 1976–77 | Trois-Rivieres Draveurs | QMJHL | 12 | 0 | 2 | 2 | 0 | — | — | — | — | — | ||
| 1977–78 | Trois-Rivieres Draveurs | QMJHL | 72 | 35 | 43 | 78 | 77 | 13 | 2 | 4 | 6 | 7 | ||
| 1977–78 | Trois-Rivieres Draveurs | M-Cup | — | — | — | — | — | 4 | 1 | 2 | 3 | 0 | ||
| 1978–79 | Trois-Rivieres Draveurs | QMJHL | 72 | 66 | 76 | 142 | 55 | 13 | 4 | 14 | 18 | 13 | ||
| 1978–79 | Trois-Rivieres Draveurs | M-Cup | — | — | — | — | — | 4 | 3 | 0 | 3 | 2 | ||
| 1979–80 | Rochester Americans | AHL | 39 | 25 | 24 | 49 | 58 | — | — | — | — | — | ||
| 1979–80 | Buffalo Sabres | NHL | 34 | 4 | 6 | 10 | 4 | 9 | 1 | 2 | 3 | 2 | ||
| 1980–81 | Rochester Americans | AHL | 69 | 21 | 29 | 50 | 101 | — | — | — | — | — | ||
| 1980–81 | Buffalo Sabres | NHL | 4 | 0 | 0 | 0 | 2 | — | — | — | — | — | ||
| 1981–82 | Rochester Americans | AHL | 56 | 37 | 37 | 74 | 45 | — | — | — | — | — | ||
| 1981–82 | Buffalo Sabres | NHL | 24 | 6 | 4 | 10 | 6 | 1 | 0 | 0 | 0 | 0 | ||
| 1982–83 | Rochester Americans | AHL | 80 | 29 | 52 | 81 | 72 | — | — | — | — | — | ||
| 1983–84 | Rochester Americans | AHL | 78 | 41 | 44 | 85 | 154 | — | — | — | — | — | ||
| 1984–85 | EHC Kloten | NLA | 36 | 42 | 26 | 68 | — | — | — | — | — | — | ||
| 1984–85 | Buffalo Sabres | NHL | 8 | 1 | 1 | 2 | 0 | — | — | — | — | — | ||
| 1985–86 | EHC Kloten | NLA | 34 | 44 | 33 | 77 | 109 | 5 | 8 | 1 | 9 | 21 | ||
| 1985–86 | Los Angeles Kings | NHL | 11 | 2 | 3 | 5 | 2 | — | — | — | — | — | ||
| 1986–87 | EHC Kloten | NLA | 29 | 25 | 22 | 47 | 44 | — | — | — | — | — | ||
| 1987–88 | EHC Kloten | NLA | 35 | 29 | 18 | 47 | 79 | 7 | 8 | 4 | 12 | 8 | ||
| 1988–89 | HC Martigny | NLB | 36 | 36 | 32 | 68 | 144 | 10 | 6 | 4 | 10 | 27 | ||
| 1989–90 | HC Sierre | NLB | 35 | 26 | 39 | 65 | 91 | 10 | 8 | 7 | 15 | 26 | ||
| 1990–91 | HC Sierre | NLA | 29 | 19 | 22 | 41 | 56 | — | — | — | — | — | ||
| 1991–92 | HC Martigny | NLB | 16 | 11 | 17 | 28 | 18 | 8 | 3 | 9 | 12 | 20 | ||
| 1992–93 | HC Martigny | NLB | 34 | 27 | 23 | 50 | 58 | 5 | 1 | 2 | 3 | 26 | ||
| 1993–94 | HC Martigny | NLB | 1 | 0 | 0 | 0 | 0 | — | — | — | — | — | ||
| NLA totals | 163 | 159 | 121 | 280 | 288 | 22 | 27 | 16 | 43 | 51 | ||||
| NHL totals | 81 | 13 | 14 | 27 | 14 | 10 | 1 | 2 | 3 | 2 | ||||