Here’s a list of the Japanese voice cast of the first series of Fullmetal Alchemist.
Source: Anime News Network

NOTE: The *s after the names mean they reprised their role in FMA Brotherhood.

Edward Elric: Romi Park*
Alphonse Elric: Rie Kugimiya*
Hohenheim: Masashi Ebara
Trisha Elric: Yoshino Takamori*

Winry Rockbell: Megumi Toyoguchi
Pinako Rockbell: Miyoko Asou*
Winry's Father (ep 3): Takehiro Murozono
Sara Rockbell (ep 3): Yuriko Yamaguchi

Roy Mustang: Toru Ohkawa
Riza Hawkeye: Michiko Neya
Jean Havoc: Yasunori Matsumoto
Heymans Breda: Tomoyuki Shimura
Kain Fuery: Tetsu Shiratori
Vato Falman: Takehiro Murozono

King Bradley/Pride: Hidekatsu Shibata*
Envy: Mayumi Yamaguchi
Greed: Junichi Suwabe
Lust: Yuuko Satou
Gluttony: Yasuhiro Takato
Wrath: Nana Mizuki
Juliet Douglas/Sloth: Yoshino Takamori

Maes Hughes: Keiji Fujiwara*
Gracia Hughes: Kotono Mitsuishi
Elysia Hughes: Mayumi Yoshida

Alex Louis Armstrong: Kenji Utsumi*
Katherine Elle Armstrong (ep 37): Rie Kugimiya*
Alex Louis Armstrong's mother (ep 37): Romi Park*

Maria Ross: Mitsuki Saiga
Denny Brosh: Masao Harada
Sheska: Naomi Wakabayashi
Tim Marcoh: Kouji Totani
General Hakuro: Jin Horikawa
Basque Grand: Shin Aomori*
Frank Archer: Sho Hayami
Zolf Kimblee: Yuji Ueda

Izumi Curtis: Shoko Tsuda*
Sig Curtis: Seiji Sasaki*
Mason: Keiichi Sonobe

Scar: Ryotaro Okiayu
Scar's Brother: Yuu Mizushima

Lyra: Yumi Kakazu
Dante (Old): Kazuko Sugiyama

Barry The Chopper: Kentarou Itou
Slicer (Older Brother): Shinya Ohtaki
Slicer (Younger Brother): Koichi Sakaguchi

Martel: Rumi Kasahara
Dolchetto: Yasunori Matsumoto
Roa/Law: Yuji Ueda

Rose Tomas: Houko Kuwashima
Priest Cornello: Kinryuu Arimoto
Cray: Akimitsu Takase
Shopkeeper (eps 1, 39): Tomohisa Asou
Man 1 (ep 1): Jin Horikawa
Man 2 (ep 1): Masao Harada
Man 3 (ep 1): Takeshi Sasaki
Man 4 (ep 1): Tsuguo Mogami

Kain (ep 2): Mitsuaki Madono
Woman (ep 2): Rin Sakurazawa
Man 1 (ep 2): Tsuguo Mogami
Man 2 (ep 2): Eisuke Asakura
Man 3 (ep 2): Ryoukichi Takahashi
Man 4 (ep 2): Kouichi Kuriyama
Man 5 (ep 2): Yoshinori Sonobe

Doctor (ep 3): Shin Aomori

Majhal (ep 4): Takaya Hashi
Clause (ep 4): Akiko Yajima
Clause's Father (ep 4): Keiichi Sonobe
Boy 1 (ep 4): Masumi Kageyama
Boy 2 (ep 4): Miwa Matsumoto
Old Policeman (ep 4): Kazuo Oka
Purse Snatcher (ep 4): Naoki Makishima

Bald: Kouji Ishii
Marin (ep 5): Emi Motoi
Marin's Mama (ep 5): Rumi Ochiai
Man with sunglasses 1 (ep 5): Kei Kurita
Man with sunglasses 2 (ep 5): Koichi Sakaguchi
Man 1 (ep 5): Eisuke Asakura
Man 2 (ep 5): Ryuuzo Hasuike
Man 3 (ep 5): Yoshihisa Kawahara
Man 4 (ep 5): Masao Harada

Shou Tucker: Makoto Nagai
Nina Tucker: Satomi Koorogi
Examinee 1 (ep 6): Katsuyuki Konishi
Examinee 2 (ep 6): Takuo Kawamura

Guard 1 (ep 7): Masao Harada
Guard 2 (ep 7): Eisuke Asakura
Clerk (ep 7): Mayumi Yamaguchi

Barry, female (ep 8): Aya Ishizu
Landlady (ep 8): Takumi Kurebayashi
Chef (ep 8): Yoshinori Sonobe

Lieutenant Yoki (ep 9): Kazuki Yao*
Kyle (ep 9): Tomoko Kawakami
Coal Mining Husband (ep 9): Naoki Makishima
Borling (ep 9): Jouji Nakata
Subordinate (ep 9): Tsuguo Mogami
Hiroyuki Yoshino (ep 9)

Clara/Psiren (ep 10): Miho Shiraishi
Obaa-chan (ep 10): Reiko Suzuki
Doctor (ep 10): Hideyuki Umezu
Middle-aged Detective (ep 10): Fumihiko Tachiki
Policeman (ep 10): Ryuuzo Hasuike

Russell Tringham: Kousuke Okano
Fletcher Tringham: Minako Arakawa
Housewife (ep 11): Masumi Kageyama
Delfino (ep 11): Kenji Nomura
Lemack (ep 11): Nobuyuki Furuta
Pharmacist (ep 11): Reiko Kiuchi
Man 1 (ep 11): Yuuto Kazama
Man 2 (ep 11): Eisuke Asakura
Elisa (eps 11-12) Motoko Kumai
Mugear (eps 11-12): Takayuki Godai
Belsio (eps 11-12): Toshihiko Seki
Nash Tringham (ep 12): Hideyuki Tanaka

Gallery 1 (ep 13): Eisuke Asakura
Gallery 2 (ep 13): Masao Harada

Child (ep 14): Mayumi Ichikawa
Farmer (ep 14): Tsuguo Mogami

Girl (ep 15): Kimiko Koyama

Brother (ep 16): Miwa Matsumoto
Sister (ep 16): Miyu Matsuki
Old man (ep 16): Takayuki Sugo

Dad (ep 17): Yoshinori Sonobe
Son (ep 17): Reiko Kiuchi

Rick (eps 18, 24): Eriko Kawasaki
Old Man (ep 18): Eiji Maruyama
Staff Member A (ep 18): Mayumi Yamaguchi
Staff Member B (ep 18): Tsuguo Mogami

Security Guard (ep 19): Eisuke Asakura

Soldier (ep 20): Ryuuzo Hasuike

Jailer A (ep 21): Yoshinori Sonobe
Jailer B (ep 21): Takehiro Murozono

Woman (ep 23): Emiko Fuku
Girl (ep 23): Touko Aoyama

Leo (ep 24): Jun Fukushima
Leo/Rick's Mother (ep 24): Yuko Kaida
Mother (ep 24): Chika Kino
Elder (ep 24): Eiji Maruyama
Wilson (ep 24): Rintarou Nishi
Mercenary 1 (ep 24): Eisuke Asakura
Mercenary 2 (ep 24): Ryoukichi Takahashi
Mercenary 3 (ep 24): Takayuki Fujimoto
Mercenary 4 (ep 24): Tsuguo Mogami
Mercenary 5 (ep 24): Yoshinori Sonobe
Mercenary 6 (ep 24): Yukio Yoda

Man (2 role) (ep 25): Takeshi Sasaki
Fatherly Master (eps 25, 30, 32, 39): Yuzuru Fujimoto

Paninya: Kyoko Hikami
Dominic: Daisuke Gouri
Woman (ep 26): Mikako Takahashi
Man A (ep 26): Daisuke Sakaguchi
Man B (ep 26): Naoki Makishima
Man C (ep 26): Makoto Aoki

General (ep 27): Masaaki Tsukada
Boy (ep 27): Michiru Yamazaki
Merchant (ep 27): Ryoukichi Takahashi
Soldier A (ep 27): Masakazu Kohara
Soldier B (ep 27): Shintarou Oohata

Boy (eps 29-30): Nana Mizuki
Priest (ep 30):Ken Fujimoto

Old Person (eps 31-32): Aikou Ogata

Soldier (ep 33): Masao Harada as
Agohige (eps 33-34): Youji Ueda

Lybia (ep 35): Fumiko Orikasa
Lujon (ep 35): Takehito Koyasu
Village Elder (ep 35): Hiroshi Naka
Master (ep 35): Koichi Sakaguchi
Man A (ep 35): Satoshi Katougi
Man B (ep 35): Shinji Matsuki
Man C (ep 35): Kouichi Kuriyama
Man D (ep 35): Takashi Kondo
Mother (ep 35): Yuki Hamano

Old General (ep 45): Masaaki Tsukada
Commanding Officer (ep 45): Shoji Izumi

Soldier A (ep 48): Hiroshi Shirokuma
Soldier C (ep 48): Ryuugo Saito

Selim Bradley (eps 49-51): Makoto Tsumura
King Bradley's Wife (eps 50-51): Asami Mukaidono
Karl Haushofer (ep 51): Masane Tsukayama
Soldier A (ep 51): Tsuguo Mogami
Soldier A (2nd role) (ep 51): Masakazu Kohara
Masane Tsukayama (ep 51)
Revy: Kazue Komiya
Man 5: Yuu Urata