-ar verb irregular · spelling-change -car B1 · Intermediate

Conjugate diagnosticar in Spanish

to diagnose

diagnosticar is an irregular -ar verb ranked #356 among the most common Spanish verbs. For example: "Yo diagnostico todos los días." (I diagnose every day.). Use the tables below for full conjugation across all 7 tenses.

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⚡ Irregular verb — diagnosticar (spelling-change -car) does not follow standard -ar patterns. Pay close attention to the stems in each tense.

Describes current actions, habits, and general truths. The most frequently used tense — master it first.

Pronoun Conjugation
yo diagnostico
diagnosticas
él/ella/Ud. diagnostica
nosotros diagnosticamos
vosotros diagnosticáis
ellos/ellas/Uds. diagnostican
Example

Yo diagnostico todos los días.

I diagnose every day.

Describes completed past actions with a clear start and end. Key signals: ayer, el lunes pasado, de repente.

Pronoun Conjugation
yo diagnostiqué *
diagnosticaste
él/ella/Ud. diagnosticó
nosotros diagnosticamos
vosotros diagnosticasteis
ellos/ellas/Uds. diagnosticaron
Example

Nosotros diagnosticamos juntos.

We diagnose together.

Describes habitual past actions, background context, and ongoing states. Key signals: siempre, normalmente, cuando era niño.

Pronoun Conjugation
yo diagnosticaba
diagnosticabas
él/ella/Ud. diagnosticaba
nosotros diagnosticábamos
vosotros diagnosticabais
ellos/ellas/Uds. diagnosticaban
Example

Antes yo diagnosticaba con frecuencia.

Before, I used to diagnose often.

Describes future events and predictions. In everyday speech, ir a + infinitive is often preferred for planned events.

Pronoun Conjugation
yo diagnosticaré
diagnosticarás
él/ella/Ud. diagnosticará
nosotros diagnosticaremos
vosotros diagnosticaréis
ellos/ellas/Uds. diagnosticarán
Example

Mañana yo diagnosticaré.

Tomorrow I will diagnose.

Expresses what would happen under certain conditions — equivalent to "would" in English. Also used for polite requests.

Pronoun Conjugation
yo diagnosticaría
diagnosticarías
él/ella/Ud. diagnosticaría
nosotros diagnosticaríamos
vosotros diagnosticaríais
ellos/ellas/Uds. diagnosticarían
Example

Si pudiera, yo diagnosticaría.

If I could, I would diagnose.

Used in clauses expressing wishes, doubt, emotion, or uncertainty — typically after que. Triggers: querer, esperar, dudar, ojalá.

Pronoun Conjugation
yo diagnostique *
diagnostiques *
él/ella/Ud. diagnostique *
nosotros diagnostiquemos *
vosotros diagnostiquéis *
ellos/ellas/Uds. diagnostiquen *
Example

Quiero que tú diagnostiques más.

I want you to diagnose more.

Used to give commands and direct requests. Affirmative and negative forms differ significantly in Spanish.

Pronoun Conjugation
yo -
diagnostica
él/ella/Ud. diagnostice
nosotros diagnosticemos
vosotros diagnosticad
ellos/ellas/Uds. diagnosticen
Example

Él diagnostica con frecuencia.

He diagnoses often.

Test yourself

Type the correct conjugation for each prompt.

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Example sentences

Common phrases with diagnosticar

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