Background: Mucositis and dermatitis complicated by bacterial and fungal infections are common in patients undergoing RT/CTRT. We intended to assess spectrum of microbial organisms in skin and oral swabs, rationality of antibiotics/anti-fungal (AB/F), toxicities, hospitalization and treatment delays. Methods: This was a prospective, single arm observational study conducted in a tertiary care hospital. 25 patients undergoing RT or CTRT from January 2014 to June 2014 were included. Patients were subjected to skin-wound and oral swab gram stain, potassium hydroxide mount, bacterial and fungal culture with sensitivity. Results: Median age was 54 years (30-69). Male: female ratio 1.5:1. Primary site: tongue 5 (20%), palate 5 (20%), tonsil, pyriform-sinus 4 (16%) each, buccal-mucosa, alveolus 2 (8%) each, EAC, nasopharynx, RMT one each (12%). 24 2D (96%) and 1 (4%) 3D planning. Feeding tube required for one (4%). 16 received concurrent cisplatin (40mg/m2 weekly), median 3 cycles. At median dose 48 (16-68 Gy) patients were referred for toxicities. Grade III,IV dermatitis were in 5(20%), 1(4%) respectively.Grade III,IV mucositis was 5(20%), 0(0%) respectively. Median laboratory parameters: hemoglobin 10.5, TLC 6350, albumin3.6 and globulin 2.8. Spectrum of organisms isolated is tabulated below. In GPC, specific isolate was Methicillin sensitive staphylococcus aureus 2, beta hemolytic streptococcus one. Four required i.v antibiotics. 3 received i.v ciprofloxacin 200mg BD and i.v metronidazole 500mg TDS, one required i.v cefoperazone-sulbactam 2 gm BD (7 days); rest 21 had adequate relief with topical antibiotics (metronidazole TDS) or antifungal (clotrimazole mouth paint TDS) alone for 7 days. Median duration of hospital stay was 10 days (2-16). Treatment interruption was in 6 ranging 6-10 days. Conclusions: Topical AB/F with adequate hydration can provide adequate symptom relief and avoid treatment interruption for mucositis and dermatitis.