Abstract. We present CCD photometry in the Washington system C and T 1 passbands down to T 1 ∼ 18.5 mag in the field of Tombaugh 1, a little studied open cluster located in the third Galactic quadrant. We measured T 1 magnitudes and C − T 1 colours for a total of 1351 stars distributed throughout an area of 13. 6 × 13. 6. A cluster radius of 4. 3 ± 0. 3 was estimated from star counts in 100-pixel a side boxes distributed throughout the entire observed field. Based on the best fits of isochrones computed by the Geneva group for Z = 0.008 to the T 1 vs. C − T 1 colour-magnitude diagram, we derive a colour excess E(C − T 1 ) = 0.55 ± 0.10, equivalent to E(B − V) = 0.30 ± 0.05, a distance of (2.2 ± 0.5) kpc from the Sun and an age of 1.3The latter value is in good agreement with that derived from the independent metallicity δT 1 index defined in Geisler et al. (1997( , AJ, 114, 1920). An independent metallicity estimation using the [M T 1 , (C − T 1 ) 0 ] plane with the standard giant branches of Geisler & Sarajedini (1999, AJ, 117, 308)