Shintaro Ishiwatari is a Japanese mixed martial artist who was born on Febraury 21, 1985 in Osaka, Japan. Ishiwatari is also the cousin of Japanese video game developer, illustrator, musician, composer and voice actor, Daisuke Ishiwatari.

Ishiwatari comes from a judo background which he trained in regularly during his school years at the Gakuen high school.

Ishiwatari began competing in amateur MMA tournaments in the year 2005. Ishiwatari participated on April 29 of that year in the Shooto Lightweight Freshman Amatuer East Tournament. Ishiwatari went on to win the tournament by winning a total of 5 fights that same day and finishing 2 of his 5 opponents in the first round by submission and KO.

Ishiwatari however decided to continue participating in amateur tournaments before turning pro, as he entered the 12th All Japan Amateur Shooto Championships in which he won his first 3 fights in the tournament by decision before losing a decision to Shooto and Bellator veteran Masakatsu Ueda.

Despite losing in the finals, Ishiwatari still decided to go pro and he made his debut on March 3, 2006 losing by TKO due to a cut in the second round to Daisuke Ishizawa. 

Ishiwatari continued to fight in Shooto racking up a record of 6 wins, 1 loss and 3 draws. In that time span, Ishiwatari fought UFC veteran Michihiro Omigawa to a draw in Shooto.

After the draw with Omigawa, Ishiwatari went on to make his Sengoku debut against "The Korean Zombie" Chan Sung Jung. In his Sengoku debut, Ishiwatari got caught in a rear naked choke by the Korean Zombie and submitted in 4:29 of the first round.

Ishiwatari continued competing and having mixed success in SRC and Shooto.

On May 3, 2011 Ishiwatari made his Pancrase debut where he fought Tashiro Nishiuchi to a draw. In his second Pancrase fight, Ishiwatari found himself in a King of Pancrase Bantamweight Title eliminator against Motonobu Tezuka. Ishiwatari went on to defeat Tezuka by split decision and then went on to defeat Manabu Inoue to earn the title.

As King of Pancrase Bantamweight champion, Ishiwatari defeated Nishiuchi who he had fought in his Pancrase debut and successfully defended his title.

On September 30, 2012 Ishiwatari made his return to the Shooto ring where he was set to face Japanese MMA legend Caol Uno. Throughout the fight, Ishiwatari showed superior striking skills to Uno rocking and dropping Uno various times throughout the fight. Ishiwatari also showed good grappling skills and submission defense, avoiding Uno's submission attempts and even German suplexing the Japanese MMA legend. The resilient legend however continued fighting Ishiwatari. Ishiwatari wasn't able to finish Uno, but he did dominate him throughout the fight entirely and he went on to win a pretty clear unanimous decision.

Ishiwatari has established himself as a Japanese 135 lb fighter to keep an eye on.