Context :

Aims : We studied the X-ray properties of the young ( \sim 1 - 8 Myr ) open cluster around the hot ( O8 III ) star \lambda Ori and compared them with those of the similarly-aged \sigma Ori cluster to investigate possible effects of the different ambient environment .

Methods : We analysed an XMM-Newton observation of the cluster using EPIC imaging and low-resolution spectral data .
We studied the variability of detected sources , and performed a spectral analysis of the brightest sources in the field using multi-temperature models .

Results : We detected 167 X-ray sources , of which 58 are identified with known cluster members and candidates , from massive stars down to low-mass stars with spectral types \sim M5.5 .
Another 23 sources were identified with new possible photometric candidates .
Late-type stars have a median \log L _ { \mathrm { X } } / L _ { \mathrm { bol } } \sim - 3.3 , close to the saturation limit .
Variability was observed in \sim 35 % of late-type members or candidates , including six flaring sources .
The emission from the central hot star \lambda Ori is dominated by plasma at 0.2 - 0.3 keV , with a weaker component at 0.7 keV , consistently with a wind origin .
The coronae of late-type stars can be described by two plasma components with temperatures T _ { 1 } \sim 0.3 - 0.8 keV and T _ { 2 } \sim 0.8 - 3 keV , and subsolar abundances Z \sim 0.1 - 0.3 Z _ { \odot } , similar to what is found in other star-forming regions and associations .
No significant difference was observed between stars with and without circumstellar discs , although the smallness of the sample of stars with discs and accretion does not allow us to draw definitive conclusions .

Conclusions : The X-ray properties of \lambda Ori late-type stars are comparable to those of the coeval \sigma Ori cluster , suggesting that stellar activity in \lambda Ori has not been significantly affected by the different ambient environment .