The Rosh Hodesh prayers are basically the same as the weekday prayers, with several additions, most notably Hallel and the Ya’aleh VeYavo paragraph. Likewise, on Rosh Hodesh the Tahanun prayer is not said, and a special Amida as an additional prayer [Musaf] is added.

Before the evening service, it is customary, mainly in Sephardic and Yemenite communities, to recite Psalms 104. This psalm includes the phrase: “He made the moon for appointed times” (Psalms 104:19), which alludes to Rosh Hodesh. In the Amida prayers of the evening, morning, and afternoon services one adds the Ya’aleh VeYavo paragraph, which mentions Rosh Hodesh. This passage appears in all daily prayer books.

One who forgot to say Ya’aleh VeYavo in the evening service is not required to repeat the Amida. But in the case of the morning and afternoon services, if one forgot Ya’aleh VeYavo and realizes his mistake only after he has already finished the Amida prayer, he must go back and recite the Amida once again, this time with Ya’aleh VeYavo. If he realized before he finished the Amida that he forgot to add Ya’aleh VeYavo, he should return to the blessing of the Temple Service (“Retzeh”), which is where Ya’aleh VeYavo is inserted, and continue from there until the end of the Amida prayer.

At the conclusion of the Amida in the morning service, following the repetition of the Amida by the prayer leader, everyone recites together the Hallel prayer, which is a sequence of chapters from the book of Psalms. The Ashkenazic custom is to recite a blessing before reciting Hallel: “Blessed are You, Lord our God, King of the universe, who sanctified us through His commandments, and commanded us to recite the Hallel,” as well as a blessing at the end of Hallel. The Sephardim do not recite blessings on the recitation of Hallel on Rosh Hodesh.

The Hallel that is recited on Rosh Hodesh is in an abbreviated form, often referred to as “half Hallel,” in which two passages are omitted, as noted in the prayer books. During Hallel there are several verses that the prayer leader reads aloud and the congregation responds after him.

After Hallel, some congregations recite the Song of the Day, which is the psalm that the Levites used to sing in the Temple on that particular day of the week. Many also add Psalms 104 (see above) at this point. In other congregations, both psalms are recited at the end of the entire prayer service. In some congregations, only Psalms 104 is recited.

Next, a Torah scroll is taken from the synagogue ark for the reading of the verses discussing the offerings that were brought in the Temple every day, on Shabbat, and on Rosh Hodesh (Numbers 28:1–15). Four men are called up for this reading: a priest, a Levite, and two ordinary Jews.

Afterward the congregation recites Ashrei (Psalms 145) and the Uva LeTzion passages, and then the Amida of the Musaf service. It is customary to remove the tefillin before reciting Musaf. There are two reasons for this:

The Musaf prayer service expresses the celebratory aspect of Rosh Hodesh, similar to that of festivals, and tefillin are not worn on festivals.

In the Musaf prayers, according to the Edot HaMizrah and Nusah Sefarad versions of the liturgy, the congregation recites: “A crown will be given to You, Lord our God,” and it is not appropriate that when a crown is given to God we should be adorned with our own crown, the tefillin.

When Rosh Hodesh occurs on Shabbat, there are several changes in the prayer services in the synagogue:

Instead of one Torah scroll, two scrolls are taken from the ark. From the first, one reads the regular Torah portion of that week, for which seven men are called up, as on every Shabbat. From the second Torah scroll the maftir is read, which consists of the verses that discuss the offerings brought in the Temple on Shabbat and Rosh Hodesh (Numbers 28:9–15).

Next, one reads the haftara (reading from the Prophets), that begins with the words: “So said the Lord: The heavens are My throne” (Isaiah 66:1–24), which includes the verse: “It shall be that on each and every New Moon and on each and every Sabbath all flesh will come to prostrate themselves before Me, said the Lord” (v. 23).

In the Musaf prayer service, the regular middle blessing for Shabbat is replaced with a blessing that begins Ata yatzarta, “You created,” which combines the themes of the Musaf prayers of Shabbat and the Musaf prayers of Rosh Hodesh.

On Rosh Hodesh it is appropriate to enhance one’s meals a bit. Some have the custom of serving a special meal to mark the day.

In Grace after Meals the Ya’aleh VeYavo section is added, with the mention of Rosh Hodesh. If one recited Grace after Meals and forgot to say Ya’aleh VeYavo, he is not required to repeat Grace after Meals.

Likewise, in the abridged Grace after Meals [Me’ein Shalosh] recited after eating foods made of grains or fruits from the Seven Species (Deuteronomy 8:8), or after drinking wine, one mentions Rosh Hodesh.

Some customarily honor Rosh Hodesh by wearing more formal attire than usual.

Many women reduce their performance of labor on Rosh Hodesh, especially household chores.

Further reading: For a kabbalistic explanation of the special connection of women to Rosh Hodesh, see A Concise Guide to Mahshava, p. 43.