Mrk 1210 is an Sa galaxy at z = 0.01350. Its optical spectrum displays a strong featureless continuum and Wolf-Rayet features within the central 200 pc (Storchi-Bergmann et al. 1998), evidencing the presence of a circumnuclear starburst. Here, we present SpeX nearinfrared (NIR) spectroscopy in the interval 0.8− 2.4 μm, combined with optical (3700A-7400A) observations, aimed at studying the physical properties of the nuclear and extended gas. Kinematics derived from the line profiles, extinction affecting the emitting gas, temperature and density indicators of the NLR, and excitation sources for the molecular and low-ionization gas are discussed. The presence of high-ionization as well as low-ionization and molecular lines in the optical and NIR spectrum suggests a strong competition between the starburst component and the ionized gas from the central engine. This makes Mrk 1210 an ideal target to study the interplay between starburst and nuclear activity in galaxies. 1. Observational results and kinematics The NIR spectrum of Mrk1210 (see Figure 1) is dominated by permitted H i and He ii lines, and forbidden lines of [S ii], [S iii] and [Fe ii]. There are also present highly ionized lines of [Sviii], [S ix], and [Six], as well as numerous H2 lines. Extended [S iii] and He i emission is found up to a distance of 500 pc from the nucleus. The analysis of the emission line profiles, both allowed and forbidden, shows a narrow (FWHM ∼ 900 km/s) line on top of a broad (FWHM ∼ 1600 km/s) blue-shifted component (∆V ∼ 120 km/s). The latter seems to be associated to a nuclear outflow, most probably located in the NLR instead of the BLR. This result rules out the presence of a hidden BLR claimed to be present in previous NIR observations of this object (Veilleux et al. 1997). 2. Reddening The numerous H i and forbidden lines in the spectra of Mrk 1210 allowed us to map the intrinsic extinction affecting the NLR by means of indicators such as the Pashen decrement and the [Fe ii] 1.257μm/1.64μm ratio. The extinction law of Cardelli, Clayton, & Mathis (1989) was used for this purpose. The results reveal a dusty AGN while the extended regions are reddening free. In the inner 200 pc we found an E(B − V ) = 0.5 from the H i lines ratios, except for Hα/Hβ from which we found E(B − V ) = 0.3, indicating differences in dust columns. From the [Fe ii] ratio 1.257μm/1.64μm a large extinction value, E(B− V ) = 1.5 was derived. This supports the hypothesis that the [Fe ii] lines are formed in a separate region, different from the classical NLR. At 250 pc from the nucleus, no extinction is found from our data. 3. Electron Density and Temperature Electronic densities and temperatures of the nuclear gas in Mrk 1210 were determined by means of several diagnostic line ratios. The results are summarized in Table 1. Notice