In 71 subjects with vascular atherosclerotic disease (VAD), in 32 VAD subjects with non‐insulin‐dependent diabetes mellitus (NIDDM) and in 31 normal controls, we evaluated polymorphonuclear leukocyte (PMN) membrane fluidity and PMN cytosolic Ca
$^{2+}$
content. The PMN membrane fluidity was obtained by marking intact and unstimulated PMN cells with fluorescent probe 1‐[4‐(trimethylamino)phenyl]‐6‐phenyl‐1,3,5‐hexatriene (TMA‐DPH) and the PMN cytosolic Ca
$^{2+}$
content was obtained by marking intact and unstimulated PMN cells with the fluorescent probe Fura 2‐AM. From the obtained results, it is evident that PMN membrane fluidity does not differentiate normals from VAD subjects and VAD subjects with NIDDM, and normals from subjects with monovascular disease (MVAD) and polyvascular disease (PVAD) with and without NIDDM. The PMN cytosolic Ca
$^{2+}$
content is significantly increased in VAD subjects and VAD subjects with NIDDM, and also in MVAD and PVAD subjects with and without NIDDM. A positive correlation is present between PMN membrane fluidity and PMN cytosolic Ca
$^{2+}$
content in normals and VAD subjects, but not in VAD subjects with NIDDM. In conclusion, in VAD subjects with and without NIDDM, an increase of the PMN cytosolic Ca
$^{2+}$
content is present; this increase might be related to the PMN spontaneous activation.
