The central claim of Christianity is that Jesus is the Jewish Messiah that was foretold in the Tenakh (Old Testament). Jews (such as myself) reject this notion.
What is a Messiah?
The word "Messiah" comes from the Hebrew word "Moshiach" and the Greek word "Kristos" (from which the word Christ is derived). The word "Moshiach" occurs in Tenakh 39 times. Here are some examples:
I Samuel 2:35 "....I will raise up a loyal kohén [priest] for Myself, who will do what is in My heart and in My mind; I will build a reliable family for him and he will walk before My messiah for all time!”
Psalm 132:17 "There I will make David's horn sprout; I have laid out a lamp for My messiah."
(context here is David, who was the anointed king) is the Messiah.
Psalm 89:39 "But You abandoned, You rejected; You became angry with Your messiah."
(clearly this particular case cannot be Jesus)
I Samuel 24:6(7) "....and he said to his men, “God forbid that I should do such a thing to my master — to Adonai’s messiah — to stretch my hand out against him; after all, he is Adonai’s messiah.”
(The messiah here is King Saul).
Jesus failed to fulfill Messianic Prophecies
1) The messiah is to bring an eternal peace between all nations and people (Isaiah 2:2-4; Micha 4:1-4; Ezekiel 39:9). Obviously there is no such peace. 40 years later, the temple was destroyed.
2) The Messiah is going to bring about universal knowlege of G-d and full Torah observance.
We have already seen that anyone who adds or subtracts from the Law is a false prophet. One of the tasks of the Messiah is to bring us back into Torah observance. 
3) Gather the Jews to Israel (Ezekie 36:24)
The Messiah is going to gather together the lost tribes of Israel and bring us back into the promise land; yet we are still lost and still in exile!
Clearly Jesus did not fulfill these prophecies. Further the prophecies attributed to Jesus are based on either: A mistranslation (i.e. Isaiah 7:14), quoting out of context, or pure fabrication (i.e. the Nazarene prophecy).