Conjugation of 'Ser'

Common Verb Is Highly Irregular

Havana for article on conjugation of ser
La Habana es la capital de Cuba. (Havana is the capital of Cuba.). Alexander Bonilla/Creative Commons license.

Ser, a verb usually meaning "to be," is one of the most irregularly conjugated verbs in Spanish. Many of the conjugated forms don't even begin with s, and some forms are shared with the highly irregular ir.

Irregular forms are shown below in boldface. Translations are given as a guide and in real life may vary with context.

Infinitive of Ser

ser (to be)

Gerund of Ser

siendo (being)

Participle of Ser

sido (been)

Present Indicative of Ser

yo soy, tú eres, usted/él/ella es, nosotros/as somos, vosotros/as sois, ustedes/ellos/ellas son (I am, you are, he is, etc.)

Preterite of Ser

yo fui, tú fuiste, usted/él/ella fue, nosotros/as fuimos, vosotros/as fuisteis, ustedes/ellos/ellas fueron (I was, you were, she was, etc.)

Imperfect Indicative of Ser

yo era, tú eras, usted/él/ella era, nosotros/as éramos, vosotros/as erais, ustedes/ellos/ellas eran (I used to be, you used to be, he be, etc.)

Future Indicative of Ser

yo seré, tú serás, usted/él/ella será, nosotros/as seremos, vosotros/as seréis, ustedes/ellos/ellas serán (I will be, you will be, he will be, etc.)

Conditional of Ser

yo sería, tú serías, usted/él/ella sería, nosotros/as seríamos, vosotros/as seríais, ustedes/ellos/ellas serían (I would be, you would be, she would be, etc.)

Present Subjunctive of Ser

que yo sea, que tú seas, que usted/él/ella sea, que nosotros/as seamos, que vosotros/as seáis, que ustedes/ellos/ellas sean (that I be, that you be, that she be, etc.)

Imperfect Subjunctive of Ser

que yo fuera (fuese), que tú fueras (fueses), que usted/él/ella fuera (fuese), que nosotros/as fuéramos (fuésemos), que vosotros/as fuerais (fueseis), que ustedes/ellos/ellas fueran (fuesen) (that I were, that you were, that he were, etc.)

Imperative of Ser

(tú), no seas (tú), sea (usted), seamos (nosotros/as), sed (vosotros/as), no seáis (vosotros/as), sean (ustedes) (be, don't be, be, let's be, etc.)

Compound Tenses of Ser

The perfect tenses are made by using the appropriate form of haber and the past participle, sido. The progressive tenses use estar with the gerund, siendo. The progressive tenses of ser are rarely used.

Sample Sentences Showing Conjugation of Ser

Ser o no ser, ésa es la cuestión. (To be or not to be, that is the question.) Infinitive (twice) and present indicative.)

Siempre he sido la rara de clase por ser pelirroja. (I've always been the odd kind for being a redhead. Present perfect and infinitive.)

Los machos y las hembras en las aves son muy diferentes. (The males and females of birds are very different. Present indicative.)

Los Padres fueron el primer equipo nacional deportivo en tener un evento para el aprecio militar. (The Padres were the first national sports team to have a military appreciation event. Preterite.)

Carmen no estudiaba, siendo el último de la clase. (Carmen didn't study, being the last in the class. Gerund.)

Éramos muy buenos hace tres meses y somos muy buenos ahora mismo. (We were very good three months ago and we are very good right now. Imperfect and present indicative.)

¿Serás una buena madre? (Will you be a good mother? Future.)

Voy a ser estrella de películas. (I'm going to be a movie star. Periphrastic future using the infinitive.)

Todos mis amigos serían perfectos personajes de una novela. (All my friends would be perfect characters for a novel. Conditional.)

Es importante que inspires a tus hijos a que sean fuertes para que crezcan sanos. (It is important that you inspire your children to be strong so that they grow up healthy. Present indicative and present subjunctive.)

Si yo fuera inteligente, no estaría aquí. (If I were smart, I wouldn't be here. Imperfect subjunctive.)

¡ feliz! (Be happy! Imperative.)