I think you meant: 私は彼に謝らないといけません。 いけません　is the negative polite verb form of いける, which means something "will do" or "is OK" or "will work". "I think that will work."　＝　 いけるかもしれません。 いけない・いけません　＝　"won't do", "you must not do", etc. So, 「私は彼に謝らないといけません。」 literally means, "If I don't apologizes to him, that won't do". Of course, nothing makes sense translated literally, and it actually means, "I need to apologize to him." A number of similar grammar structures exist in Japanese that consist of a verb in the negative form followed by the connector と, or the conditional negative verb form ~なければ, or the negative verb form nなくて followed by は, and finally a negative phrase. ？？？ないとだめ ？？？ないといけません ？？？なければ、なりません ？？？なくてはいけません 謝らないとだめ 謝らないといけません 謝らなければなりません 謝らなくてはいけません I've always thought that it was interesting that a double negative becomes a "must do" in Japanese; saying "not doing X would be bad" is a common way of saying "I (or you) have to/should/must/need to do X". 謝る必要がある　is the more literal translation from English (I need to apologize). This isn't grammatically incorrect, but I don't hear it used as often, and it has a slightly different nuance than the other phrases above.